Credit Card Authorization

Gurus,
I am investigating implementing an online real-time credit card 
authorization system via an AS/400 RPGILE user interface.
The information, options and advice I am getting is both overwhelming and 
confusing.
Every search seems to keep pointing me to third party products;
some that must display a web page
some with crazy transaction charges,
some...
Use Net.Commerce, GO JavaCard, WebSphere Payment Mangaer,...??? Are these 
current, up-to-date?

My faith in the AS/400 leads me to believe that I should be able to 
implement a system that doesn't  involve a third party and runs on a green 
screen.

Screen 1. Please Enter Credit Card Number/Date etc, : 
_________________________ <enter>

Screen 2. Processing Authorization Request. Please Wait.

Screen 3. Approved. Yay!

Is this blind faith?

Please if anybody has some clue regarding weather this is possible, Yay or 
Nay me.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Troy Bryant 
Analyst Programmer
Patrick Autocare.
Phone: +61 03 9926 9913
Fax: +61 03 9926 9977
Mobile: +61 0408 397 333
T.Bryant@xxxxxxxxxxxxxx