The advanced Avalaunch feature (which was just SITE REFRESH) was removed from Qwix 1.01. If you're not using 1.01, you should update. It's got a few fixes that really make Qwix stable.
As for doing the other SITE commands, I'll add some support for that when I can focus on the FTP client some more. I'm in the middle of an overhaul of some of the inner workings of Qwix so the next release probably won't add too many new bells and whistles. The one after that will.