Hi Laurent DANESI,
Straight to your questions:
Few controls are available only in Silverlight, but normally this is due to the specifics of Silverlight - the RadUpload, RadHtmlPlaceholder and the MediaPlayer are available only for Silverlight and the RadCarousel is available only for WPF (because of some WPF-specific features it uses).
The naming of the controls is the same, as is the naming of their members.
As you know Silverlight is a subset of WPF. We have designed the Silverlight controls to offer some of the WPF built-in functionality - this includes the HierarchicalDataTemplate, the RadDockPanel the DataTemplateSelctors, RoutedEvents and more.
In this case we rely on WPF and do not offer a telerik HierarchicalDataTemplate for example but rely on the one already present in WPF. This approach is only taken for "building blocks" elements.
In this case the <telerik:HierarchicalDataTemplate />
needs to be replaced with <HierarchicalDataTemplate />
Do come back to us with more questions or suggestions,
the Telerik team