Maintain Subscreen for Coding Block

Dear Guys

I have a requirement to create a subscreen for a FI transaction. I know that this can be done using OXK1. I have already created a subscreen. But I want to know that how can I link that subscreen with a particular Transaction.

e.g I have made a subscreen in Maintain Subscreen for Coding Block. Now how can I guess which transaction will call this sucscreen.

As a ABAPER I think there would some user exit or enhancement through which we call these subscreens for a particular Transaction.

Pls give a detailed answer, I have created a subscreen but dont know how to link it with a particular T-Code in FI

. Thnx