Hi, where and how do I turn off auto commit?

I'm experiencing the following behavior:

IBO 4.9.9 + FB 2.1 + Delphi 2006 + Win 7 HP

uDM I have ib_connection -> ib_querys -> ib_datasources
uPrincipal calls uCustomer

in uCustomer I have buttons for Insert, Delete, Alter, etc..., and
several ibo controls
If I do a dm.qrCustomer.Insert, and close the form, the row is posted
(in form.onClose I close dm.qrCustomer)
If I exit the application, the row is posted too.

I'm sure this is about auto-commit, but please note that I have no
ib_transaction explicit in DM, I always use
ib_query.ib_transaction.commitretaining or rollbackretaining.

Is there any way I can turn auto-commit off maintaining this scenario
with no ib_transaction object explicit dropped in DM?

[]s
Andrei