By initial design the RadDock's ContentTemplate was set with [TemplateInstance(TemplateInstance.Single)]
attribute, so that the controls inserted in the content of a RadDock can be accessed in the code-behind. This is causing problems when a RadDock, containing server controls with identical IDs, is added both in the ItemTemplate and the EditItemTemplate of a FormView.
Currently the only approach I can suggest to you would be to populate the RadDocks with controls that have unique IDs.
All the best,
the Telerik team