Using the Skin property works, but double click client side does not. Double click problem is related to RadFileExplorer control in version Q3 SP2 of Telerik.Web.UI which we use. The problem is sorted out in Q1 of Radcontrols. We will include Q1 in the upcoming Service Pack of Sitefinity. You can experimient by replacing current Telerik.Web.UI with Q1 2009.
I hope this helps.
the Telerik team
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