You said "I want it on Disk 0 so I can have a dual boot setup . I don't want to lose my original Vista Ultimate installation since this is not a production OS yet."
That is what you want. With all that space on discs x,y,z,etc,etc,etc. why don't you just install W7RC to disk1 or disc2? You would still have dual boot. Anyway, it worked for me. And I dual boot Vista Home Basic 32bit with W7RC Ultimate 64bit. Leave disc0 to Vista, I say.