Database Software

I have a very odd problem. I have a scheduled job which calls a proc. this proc is set to execute with the definers privs. this works fine when I execute the proc or the dbms_scheduler.run_job as another database user. However when the scheduler runs, the proc does not appear to have the owners permissions!

This has only been an issue when there is a database link involved.

Anyone know why this would be?

Can anyone tell me which database user dbms_scheduler runs as and if this can be changed? I really need the scheduler to run with the privs of a certain user and really I need it to be that user - to have same password/username as the user on the other database for the database link. (I'm wanting to periodically copy data from one database to another)

anyway help much appreciated!