Thank you for writing.
In order to specify a back color for the RadTileElement
only for the normal state and don't affect the mouse over
or other states, you can use the API for overriding theme settings at run time: http://docs.telerik.com/devtools/winforms/telerik-presentation-framework/override-theme-settings-at-run-time
Here is a sample code snippet which will change the back color of the tile but keep its hover state:
I hope this information helps. Should you have further questions I would be glad to help.
Telerik by Progress