Payment gateway integration

Hello all,

I apologize if this has been covered previously, but I couldn't seem to find
a way to search the list archives.  I'm interested in finding out if anyone
has any information regarding integrating a payment gateway in to
NoCatAuth's splash page style system.  Basically what I want to do is
similar to what Starbucks does at their coffee shops.  A user logs on the
wlan and goes to a page where they can buy access to the Internet by the
day, hour, or whatever.  Actually, I think Starbucks does the actual payment
transaction at the register, but what I'd like to do is set up a method of
charging a credit card through the captive portal.

This is for a hotel's broadband system which is already in place.  They have
a wlan which is just connected to a DSL line with a plain old router.  What
they want to do is replace the router with a PC running some sort of captive
portal which would make the hotel guests pay for their Internet access.

>From what I have read NoCat supports several authentication methods.  If I
could redirect the user out to a secure site on the Internet where they
could complete their payment transaction, and then have that site send some
kind of response back to NoCat when the transaction is approved, I could
avoid trying to figure out someway to integrate some sort of hacked together
payment system on the NoCat box.  In theory this response would tell NoCat
that this user (mac address, or whatever) should be allowed access until
such and such time.

Any of this sound feasible, or am I way off base thinking this could be
accomplished?

Many thanks,
Fred