Also Julio,
These are few links which will be useful to you:
Partial code commit in standard User-Exits
What can be used instead of COMMIT WORK in a user exit?
Using COMMIT WORK in User Exit or in BADI
Call function module IN Update Task
Can I Call Update task function module in a User Exit?
There are plenty discussions available on this subject here: Google
Good luck
KJogeswaraRao