The following xaml does not seem to work:
<telerik:RadRibbonButton telerik:ScreenTip.Description="Start a new section at the current position." LargeImage="pack://application:,,,/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/32/PageBreak.png" telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding InsertSectionBreakCommand}" Size="Large" Text="Section Break" telerik:ScreenTip.Title="Section Break" />
There seems to be such a command asInsertSectionBreakCommand, but it does no seem to be implemented or something