Hi, sorry to open an old thread but the order of registration seems to be a problem for me too. Did something change again in Q3 2009?
I notice that my theme's specificity is IDENTICAL to that of the base skin being registered in WebResource, but because the WebResource CSS is called last on Render (why?!) I'm stuck with the base skin not the custom skin from my ASP.NET Theme.
So I'm left with two options it seems. Either a) go through my entire theme and add !important to everything (this would be ridiculous) or b) somehow increase the specificity for each class in my custom theme even further.
a) really isn't an option, but b) is incredibly annoying as well. Note that I didn't have this problem prior to upgrading to Q3 2009. Plus, I followed your "custom skin in an ASP.NET Theme" documentation, which is perhaps no longer valid?
Please advise - is b) really my best option?