I've got the Avid CPS discs on my new bike. They are awesome. I test rode a bike with Hayes hydraulics the same day I bought this bike and couldn't tell any difference. No noise and super powerful. Plus set up is a snap compared to hydraulics. And half the price.
Don't know about the adaptor though. You might try Avids site and see what they say about it. They have some installation manuals in PDF form. DG
Avid Link