I'm sorry, but I can't seem to remember what had to be changed in the signup.php. I think you just had to edit that one so that all of your fields are captured.
I also remember, that you have to go to your mysql database for NIXT WHM and make the monthly billing amount for each of your plans equal to your recurreing part number at 2checkout. You have to do it through mysql and not the NIX WHM because the WHM will add a ".0" to the end of the number, and when your form posts to 2chekcout, it will not recognize it.
So for example, for Plan 1, monthly you charge $7.95, and the part number at 2checkout is 15. Instead of putting $7.95 in billing amount in the NIXT WHM, you put 15. Then go to the mysql Database for NIXWHM and change the 15.0 to 15.
Hope that helps. Let me know if you get to a point and need more help, I will do my best to give you help.
cPanel.net Support Ticket Number: