accepting paypal on cgi site

["Jim Franz" <franz400@xxxxxxxxxxxx>]

Customer wants to accept Paypal payment on their current rpg/cgi site
for their customers A/R statement. 
Most likely only a couple trans a day, all for different amounts. 
Read thru the Paypal developer site. 
I'm sure others have done this - 
The basic HTML Checkout Cart Upload method with only 1 item seems to fit this situation.
Questions:
1. since what customer pays is will get applied - do I need the encryption 
options? (if yes - would like some idea how on iSeries)
2. Did not see any option from Paypal other than email for payment confirmation - it there a way to get transaction record (immediate - need to release a credit lock on new orders if payment made). 

Would prefer working in the rpg/cgi and not having to install/load php - I see plenty of php info on paypal..customer looking for a "quick fix".