Huh? The init file controls a single database, so if he's willing to do the work he can create you your own little database with nls date format set correctly and it won't affect any of the others ...
The obvious thing I'm missing, though, is why you're not running OpenACS with Postgres :)
If I had my druthers , I WOULD be running PostgreSQL.. but this being a big company project, they want to interface with Oracle.. on the bright side, they didnt make me use IIS :)