Using the session variables only for posting payment - no DB involvement

[Sam37]

I need to implement a payment which will send the $_SESSION [ccdata] values (All Credit cards details)
The values will be sent by POST method of the form to https://demo.mypaymentprocessordemo.com. And get the result code back to the shop.

I have read a lot of messages here, I still have some questions:
I am new to PHP (but not to programming), and by reading the forum and support files, trying to figure out the best way to implement this.

1. Can anyone direct me to a document or message that explains the content of virtuemart session variables?
2. I am not allowed to save the credit card data in the database. How would I take the data on the fly?
3. Where can I find details about the $d array (passed as reference type argument) payment processing functions in the code?
4. Should I use one of the existing payment classes (which one?) or make new one?

Any help is greatly appreciated, if someone can offer a paid job or paid tutoring me on this one, I'll be happy to hear.
Thanks,
Sam.