EFS problem during migration from Vista 5600 -> RTM

My situation:

* had Vista 5600 (RC1).
* encrypted files & folders with it.
* exported the PFX cert but not the CER
* installed Vista RTM as a new install - 5600 version is now under
windows.old. Same user name.
* imported the backed-up PFX into the new install
* can't access the encrypted files ((

Any way for me to fix this? Presumably the data is all still there. E.g.,
any way to log into the .old version so I can export a .CER, or just get it
directly somehow?

Thanks,

Sai