Sample Module for Creating Fixed Record Format File

After checking out a customer I need to build a fixed record length format file with shipping and payment data, encode it with PGP, and FTP it over to an order fulfillment and payment processing center (which requires both CC# and CVV#), at which point the order will be totally out of my hands. I only plan to store the first and last 4 digits of the CC# in my DB.

I have a basic idea on how I'd structure such a PHP script (although I'm still unclear on how to use PGP and FTP through PHP -- but I'm assuming Google will help), but I was hoping someone might know of a preexisting module upon which I could build.

Could anyone possibly point me in the right direction?

In case anyone's familiar with them, the order fulfillment/processor company is GSI Com merce

Switching to another processor isn't an option.