Integrating IWP and paypal

I am building a solution that emails a password protected pdf file (cool new feature of FM 8) to landlords. The pdf file contains prospective tenant contact information that landlords can purchase. I'd like to enable the landlord to be able to purchase a code to open the pdf file by clicking a buy now paypal button embedded in the email containing the pdf. If after clicking the button in the email, paying and successfully completing the transaction, then they would go to a success page that would give the code to unlock the pdf file in the email. The problem is that I am assuming the code would be generated within FMP (based on info from the customer table, ie: name+Phone, etc.). How would one be able to generate a success html page that contains the dynamicly generated code from FMP? Can you mix IWP and CWP to achieve something like this? Thanks in advance!!!