How about this ...
1. Backup my old ubb
2. delete all forums except the one that has my valuable post in it
3. rename the remaining forum to something that won't collide when imported
4. delete all users except myself
5. delete all banlists
6. Do the import
Would this work?
If so, what about my account existing in both the soruce of the import and dest? whould that bork things?