Validating Users with Paypal IPN

[bgro]

Hello,

I am attempting to have users register and pay for a custom content area of my website.  I am using FEUsers, SelfReg, and CustomContent.  What I am trying to do is have the customer validated (SelfReg Email Validation Process) after paypal IPN has been sent.  I'm not sure exactly how I am going to tie the two together.  Is there a way to send the registration code (from SelfReg) to paypal and have it sent back with the IPN when approved?  I could then easily have a script handle the rest.  Maybe there is a better way to do this.  Any help would be beneficial! 

p.s. I can't figure out how to set the default expiration date entered when users signup with self registration...  Currently it is 5 years.