Yes, you can use themes to change the appearance of the map and its controls. You can specify the StyleManager.Theme attachable property. Also when you use a theme then you should reference its dll in your project.
Also you can use standard approach for restyling the navigation control using your own styles. The sample code is below.
<
UserControl
x:Class
=
"SilverlightApplication1.MainPage"
xmlns:system
=
"clr-namespace:System;assembly=mscorlib"
mc:Ignorable
=
"d"
d:DesignHeight
=
"300"
d:DesignWidth
=
"400"
>
<
UserControl.Resources
>
<
LinearGradientBrush
x:Key
=
"ControlOuterBorderVertical_Normal"
EndPoint
=
"1,0.5"
StartPoint
=
"0,0.5"
>
<
GradientStop
Color
=
"#FFA9BFD6"
/>
<
GradientStop
Color
=
"#FFCDDAEA"
Offset
=
"1"
/>
</
LinearGradientBrush
>
<
Thickness
x:Key
=
"MapCommandBarMargin"
>6,0</
Thickness
>
<
Thickness
x:Key
=
"MapZoomBarMargin"
>6,0</
Thickness
>
<
SolidColorBrush
x:Key
=
"MapArrowShadow"
Color
=
"White"
/>
<
system:Double
x:Key
=
"MapNavigationSize"
>74</
system:Double
>
<
Visibility
x:Key
=
"MapArrowVisibility"
>Visible</
Visibility
>
<
SolidColorBrush
x:Key
=
"MapNavigationCenterEllipseBackground"
Color
=
"Transparent"
/>
<
SolidColorBrush
x:Key
=
"MapNavigationCenterEllipseStroke"
Color
=
"Transparent"
/>
<
Visibility
x:Key
=
"MapNavigationCenterEllipseVisibility"
>Collapsed</
Visibility
>
<
SolidColorBrush
x:Key
=
"MapNavigationCenterOuterEllipseStroke"
Color
=
"Transparent"
/>
<
Style
x:Key
=
"MapNavigationButton"
TargetType
=
"telerik:RadButton"
>
<
Setter
Property
=
"Foreground"
>
<
Setter.Value
>
<
LinearGradientBrush
EndPoint
=
"1,1"
StartPoint
=
"0,0"
>
<
GradientStop
Color
=
"#FF1E395B"
Offset
=
"0.004"
/>
<
GradientStop
Color
=
"#FFC3E4F5"
Offset
=
"1"
/>
<
GradientStop
Color
=
"#FF4C607A"
Offset
=
"0.5"
/>
</
LinearGradientBrush
>
</
Setter.Value
>
</
Setter
>
<
Setter
Property
=
"Width"
Value
=
"30"
/>
<
Setter
Property
=
"Height"
Value
=
"30"
/>
</
Style
>
<
Style
x:Key
=
"MapNavigationLeftButton"
BasedOn
=
"{StaticResource MapNavigationButton}"
TargetType
=
"telerik:RadButton"
>
<
Setter
Property
=
"Padding"
Value
=
"0,0,12,0"
/>
<
Setter
Property
=
"Background"
>
<
Setter.Value
>
<
LinearGradientBrush
EndPoint
=
"1,0.5"
StartPoint
=
"0,0.5"
>
<
GradientStop
Color
=
"#FFFDFEFF"
Offset
=
"0"
/>
<
GradientStop
Color
=
"#FFDDE9F7"
Offset
=
"1"
/>
<
GradientStop
Color
=
"#FFE6F0FA"
Offset
=
"0.5"
/>
<
GradientStop
Color
=
"#FFDCE6F4"
Offset
=
"0.5"
/>
</
LinearGradientBrush
>
</
Setter.Value
>
</
Setter
>
<
Setter
Property
=
"CornerRadius"
Value
=
"9,15,15,9"
/>
</
Style
>
<
Style
x:Key
=
"MapNavigationRightButton"
BasedOn
=
"{StaticResource MapNavigationButton}"
TargetType
=
"telerik:RadButton"
>
<
Setter
Property
=
"Padding"
Value
=
"12,0,0,0"
/>
<
Setter
Property
=
"Background"
>
<
Setter.Value
>
<
LinearGradientBrush
EndPoint
=
"0,0.5"
StartPoint
=
"1,0.5"
>
<
GradientStop
Color
=
"#FFFDFEFF"
Offset
=
"0"
/>
<
GradientStop
Color
=
"#FFDDE9F7"
Offset
=
"1"
/>
<
GradientStop
Color
=
"#FFE6F0FA"
Offset
=
"0.5"
/>
<
GradientStop
Color
=
"#FFDCE6F4"
Offset
=
"0.5"
/>
</
LinearGradientBrush
>
</
Setter.Value
>
</
Setter
>
<
Setter
Property
=
"CornerRadius"
Value
=
"15,9,9,15"
/>
</
Style
>
<
Style
x:Key
=
"MapNavigationUpButton"
BasedOn
=
"{StaticResource MapNavigationButton}"
TargetType
=
"telerik:RadButton"
>
<
Setter
Property
=
"Padding"
Value
=
"0,0,0,12"
/>
<
Setter
Property
=
"Background"
>
<
Setter.Value
>
<
LinearGradientBrush
EndPoint
=
"0.5,1"
StartPoint
=
"0.5,0"
>
<
GradientStop
Color
=
"#FFFDFEFF"
Offset
=
"0"
/>
<
GradientStop
Color
=
"#FFDDE9F7"
Offset
=
"1"
/>
<
GradientStop
Color
=
"#FFE6F0FA"
Offset
=
"0.5"
/>
<
GradientStop
Color
=
"#FFDCE6F4"
Offset
=
"0.5"
/>
</
LinearGradientBrush
>
</
Setter.Value
>
</
Setter
>
<
Setter
Property
=
"CornerRadius"
Value
=
"9,9,15,15"
/>
</
Style
>
<
Style
x:Key
=
"MapNavigationDownButton"
BasedOn
=
"{StaticResource MapNavigationButton}"
TargetType
=
"telerik:RadButton"
>
<
Setter
Property
=
"Padding"
Value
=
"0,12,0,0"
/>
<
Setter
Property
=
"Background"
>
<
Setter.Value
>
<
LinearGradientBrush
EndPoint
=
"0.5,1"
StartPoint
=
"0.5,0"
>
<
GradientStop
Color
=
"#FFFDFEFF"
Offset
=
"0"
/>
<
GradientStop
Color
=
"#FFDDE9F7"
Offset
=
"1"
/>
<
GradientStop
Color
=
"#FFE6F0FA"
Offset
=
"0.5"
/>
<
GradientStop
Color
=
"#FFDCE6F4"
Offset
=
"0.5"
/>
</
LinearGradientBrush
>
</
Setter.Value
>
</
Setter
>
<
Setter
Property
=
"CornerRadius"
Value
=
"15,15,9,9"
/>
</
Style
>
<
Style
x:Key
=
"MapNavigationCenterButton"
BasedOn
=
"{StaticResource MapNavigationButton}"
TargetType
=
"telerik:RadButton"
>
<
Setter
Property
=
"Background"
>
<
Setter.Value
>
<
LinearGradientBrush
EndPoint
=
"0.5,1"
StartPoint
=
"0.5,0"
>
<
GradientStop
Color
=
"#FFFDFEFF"
Offset
=
"1"
/>
<
GradientStop
Color
=
"#FFDCE6F4"
/>
</
LinearGradientBrush
>
</
Setter.Value
>
</
Setter
>
<
Setter
Property
=
"CornerRadius"
Value
=
"13"
/>
<
Setter
Property
=
"Width"
Value
=
"26"
/>
<
Setter
Property
=
"Height"
Value
=
"26"
/>
</
Style
>
<
Style
x:Key
=
"MapDropDownButton"
TargetType
=
"telerik:RadDropDownButton"
>
<
Setter
Property
=
"Width"
Value
=
"36"
/>
<
Setter
Property
=
"Height"
Value
=
"26"
/>
<
Setter
Property
=
"CornerRadius"
Value
=
"3"
/>
<
Setter
Property
=
"Background"
>
<
Setter.Value
>
<
LinearGradientBrush
EndPoint
=
"0.5,1"
StartPoint
=
"0.5,0"
>
<
GradientStop
Color
=
"#FFFDFEFF"
Offset
=
"0"
/>
<
GradientStop
Color
=
"#FFDDE9F7"
Offset
=
"1"
/>
<
GradientStop
Color
=
"#FFE6F0FA"
Offset
=
"0.5"
/>
<
GradientStop
Color
=
"#FFDCE6F4"
Offset
=
"0.5"
/>
</
LinearGradientBrush
>
</
Setter.Value
>
</
Setter
>
<
Setter
Property
=
"BorderBrush"
Value
=
"{StaticResource ControlOuterBorderVertical_Normal}"
/>
</
Style
>
<
Style
x:Key
=
"MapCommandBarButton"
BasedOn
=
"{StaticResource MapDropDownButton}"
TargetType
=
"telerik:RadDropDownButton"
>
</
Style
>
<
Style
x:Key
=
"MapZoomBarButton"
BasedOn
=
"{StaticResource MapDropDownButton}"
TargetType
=
"telerik:RadDropDownButton"
>
</
Style
>
<
Style
TargetType
=
"telerik:MapNavigation"
>
<
Setter
Property
=
"IsTabStop"
Value
=
"False"
/>
<
Setter
Property
=
"Template"
>
<
Setter.Value
>
<
ControlTemplate
TargetType
=
"telerik:MapNavigation"
>
<
Grid
x:Name
=
"mapNavigation"
HorizontalAlignment
=
"Center"
VerticalAlignment
=
"Center"
Width
=
"{StaticResource MapNavigationSize}"
Height
=
"{StaticResource MapNavigationSize}"
>
<
telerik:RadButton
x:Name
=
"PART_ArrowLeft"
HorizontalAlignment
=
"Left"
Style
=
"{StaticResource MapNavigationLeftButton}"
>
<
telerik:Arrow
Direction
=
"Left"
Visibility
=
"{StaticResource MapArrowVisibility}"
/>
</
telerik:RadButton
>
<
telerik:RadButton
x:Name
=
"PART_ArrowRight"
HorizontalAlignment
=
"Right"
Style
=
"{StaticResource MapNavigationRightButton}"
>
<
telerik:Arrow
Direction
=
"Right"
Visibility
=
"{StaticResource MapArrowVisibility}"
/>
</
telerik:RadButton
>
<
telerik:RadButton
x:Name
=
"PART_ArrowUp"
VerticalAlignment
=
"Top"
Style
=
"{StaticResource MapNavigationUpButton}"
>
<
telerik:Arrow
Direction
=
"Up"
Visibility
=
"{StaticResource MapArrowVisibility}"
/>
</
telerik:RadButton
>
<
telerik:RadButton
x:Name
=
"PART_ArrowDown"
VerticalAlignment
=
"Bottom"
Style
=
"{StaticResource MapNavigationDownButton}"
>
<
telerik:Arrow
Direction
=
"Down"
Visibility
=
"{StaticResource MapArrowVisibility}"
/>
</
telerik:RadButton
>
<
Ellipse
StrokeThickness
=
"5"
Width
=
"47"
Height
=
"47"
VerticalAlignment
=
"Center"
HorizontalAlignment
=
"Center"
Fill
=
"{StaticResource MapNavigationCenterEllipseBackground}"
Stroke
=
"{StaticResource MapNavigationCenterEllipseStroke}"
Visibility
=
"{StaticResource MapNavigationCenterEllipseVisibility}"
/>
<
Ellipse
HorizontalAlignment
=
"Center"
VerticalAlignment
=
"Center"
StrokeThickness
=
"1"
Height
=
"47"
Width
=
"47"
Stroke
=
"{StaticResource MapNavigationCenterOuterEllipseStroke}"
Visibility
=
"{StaticResource MapNavigationCenterEllipseVisibility}"
/>
<
telerik:RadButton
x:Name
=
"PART_CenterButton"
Style
=
"{StaticResource MapNavigationCenterButton}"
/>
</
Grid
>
</
ControlTemplate
>
</
Setter.Value
>
</
Setter
>
</
Style
>
</
UserControl.Resources
>
<
Grid
x:Name
=
"LayoutRoot"
Background
=
"White"
>
<
telerik:RadMap
x:Name
=
"radMap"
>
<
telerik:RadMap.Provider
>
<
telerik:OpenStreetMapProvider
/>
</
telerik:RadMap.Provider
>
</
telerik:RadMap
>
</
Grid
>
</
UserControl
>