I think RC1 suffers the same problems as milestone 7. Does anyone know when these issues will be resolved?
If you look at the Eclipse WST site here http://www.eclipse.org/webtools/index.html, they claim to be having a milestone release around the start of July that covers Eclipse 3.1. I would guess that the IDE cannot be available much before that - although it would certainly make my life (and my coworkers lives) easier if it were available before that.
I did try and grab the integration builds off the WST site - I first backed up my eclipse installation directory and workspace. I had little luck getting it going and I did need to restore everything.