Customize Seeded NACHA

Hi,

I am trying to customize the seeded NACHA process. I have created a custom version of it and also created the concurrent program. Since the concurrent program calls the executable PYUGEN, I do not know where to attach my code so that the custom version of the package is called instead of the seeded version. This is done because:

1. If user runs the seeded concurrent program NACHA then the seeded version of package PAY_US_NACHA_TAPE gets executed

2.  If user runs the CUSTOM concurrent program XX_NACHA then the  CUSTOM version of package XX_PAY_US_NACHA_TAPE gets executed.