Create several UserControls like UC1, UC2, UC3 etc. Then instead of putting Image items in the Collection add the user controls.
Other way would be to implement the rotator yourself. Add a ContentControl on the page. Create a DispatcherTimer, Start it and on each tick change the Content property of the ContentControl with your custom UserControls. You can then replace the ContentControl with RadTransitionControl and it should still work this time with transitions.
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