I finally figured out the process of creating and adding the custom skin assembly and have it work by studying your attached zip file (http://www.telerik.com/community/code-library/aspnet-ajax/general/how-to-load-skins-from-external-assemblies.aspx). My question is how do I add my custom skin to the list of defined skins that ship in telerik's version of Telerik.web.ui.skins. If I reference telerik's dll in the assembly then my custom skin doesn't show in the skin chooser. If I reference telerik's dll in the web reference list then I also loose the custom skin. How do you combine the both the telerik predefined skins and the custom skin together so they all show up in the chooser drop down list?