RadioButton Group Binding

[ITA]

Hi,

i use a RadGridView like this:

<telerik:RadGridView Grid.Row="2" Grid.Column="0" Margin="10,10,10,0" FontFamily="Tahoma" FontSize="12" x:Name="radGridView" AutoGenerateColumns="False" CanUserReorderColumns="False" CanUserInsertRows="False" CanUserDeleteRows="False" ShowColumnFooters="False" CanUserFreezeColumns="False" RowIndicatorVisibility="Collapsed" >
            <telerik:RadGridView.ColumnGroups>
                <telerik:GridViewColumnGroup  Name="Lokal" Header="lokal DB" />
                <telerik:GridViewColumnGroup  Name="abas" Header="abas-ERP" />
            </telerik:RadGridView.ColumnGroups>
            <telerik:RadGridView.Columns>
                <telerik:GridViewDataColumn DataMemberBinding="{Binding AbasID}" Header="abas-ID" IsReadOnly="True" Width="70" UniqueName="AbasID" ColumnGroupName="Lokal"  />
                <telerik:GridViewDataColumn DataMemberBinding="{Binding Versionn}" Header="Versionn" IsReadOnly="True" Width="auto" UniqueName="Versionn" ColumnGroupName="Lokal" />
                <telerik:GridViewDataColumn DataMemberBinding="{Binding Feldname}" Header="Feldname" IsReadOnly="True" Width="auto" UniqueName="Feldname" ColumnGroupName="Lokal" />
                <telerik:GridViewDataColumn DataMemberBinding="{Binding Feldwert}" Header="Feldwert" IsReadOnly="True" Width="*" UniqueName="Feldwert" ColumnGroupName="Lokal" />
                <telerik:GridViewColumn Header="<<" ColumnGroupName="Lokal" Width="auto">
                    <telerik:GridViewColumn.CellTemplate>
                        <DataTemplate >
                            <telerik:RadRadioButton IsChecked="{Binding Syncabastolokal, Mode= TwoWay}" GroupName="Sync" x:Name="Syncabastolokal" Height="25" Width="50"/>
                        </DataTemplate>
                    </telerik:GridViewColumn.CellTemplate>
                </telerik:GridViewColumn>

                <telerik:GridViewColumn Header=">>" ColumnGroupName="abas" Width="auto">
                    <telerik:GridViewColumn.CellTemplate>
                        <DataTemplate>
                            <telerik:RadRadioButton IsChecked="{Binding Synclokaltoabas, Mode= TwoWay}" GroupName="Sync" x:Name="Synclokaltoabas" Height="25" Width="50"/>
                        </DataTemplate>
                    </telerik:GridViewColumn.CellTemplate>
                </telerik:GridViewColumn>
                <telerik:GridViewDataColumn DataMemberBinding="{Binding Xabasid}" Header="abas-ID" IsReadOnly="True" Width="70" UniqueName="XAbasID" ColumnGroupName="abas"/>
                <telerik:GridViewDataColumn DataMemberBinding="{Binding Xversionn}" Header="Versionn" IsReadOnly="True" Width="auto" UniqueName="Xversionn"  ColumnGroupName="abas"/>
                <telerik:GridViewDataColumn DataMemberBinding="{Binding Xfeldname}" Header="Feldname " IsReadOnly="True" Width="auto" UniqueName="Xfeldname"  ColumnGroupName="abas"/>
                <telerik:GridViewDataColumn DataMemberBinding="{Binding Xfeldwert}" Header="Feldwert " IsReadOnly="True" Width="*" UniqueName="Xfeldwert"  ColumnGroupName="abas"/>
            </telerik:RadGridView.Columns>
        </telerik:RadGridView>

Why does the binding of the radiobuttons not work? If a select one RadionButton in a row the selection of the previous row is away.

Thanks
Rene