hmm weird. i just played around with rocketdock for a bit to try and see if it will do what your saying but no luck. If you cant get it to work you could try and replace the background image of another skin with the one from SoftGlass and see if that works
Sorry, didn't quite make that clear. In this case, the background doesn't look right, instead it looks just like the default glass. I checked, and all the files got copied to Rocketdock's skin folder correctly, but it still just loads the default dock vs the SoftGlass one.