I'm not understanding where the commit is located. Is it in the stored proc following the DML, or is it in the script that calls the stored proc? If the commit is in the stored proc, you're out of luck. If it's in the script, what you're thinking should work. The default for the 'c' option is autocommit on, so issuing the 'c' option will turn autocommit off.
But like ARWinner said, test it to make sure. If you can't run the same stored procs in a test environment, create new ones for yourself.