Personally, I know partitioning with eollie's oneclick works. It's the first one in the second post of my oneclick thread. Also check out lumin30's oneclick guide.
Reboot to recovery, nandroid backup (using an SD card that works) . Put device in download mode and oneclick. Put the SD card in, partition.
At this point I hope you report back
Flash your rom's zip so it's the same version as you backed up with. Same recovery. Nandroid restore your backup.
Worth a shot.
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