Inplace upgrade with Hard drive swap

SCCM 2007 with an SMP.

I want to do an inplace upgrade.  Current machine is WinXP.  The idea is to run a USMT Capture, replace the hard drive, then run an OSD on the new drive, and a restore.

The problem is, because I'm swapping drives, I can't really create a computer association for the SMP, so I can't restore the data.  The inplace association doesn't work because it's a new SCCM Client/Guid and a side by side association can't be created because the MAC address is already in use by the old Comp object.

How can I do this?  Anyone with any ideas?

Thanks!