I need to have custom Payment Option via VX Gateway

[dsmith1955]

I am using versions of Joomla 2.5.11 and Virtuemart version 2.0.20b.  I have a customer that needs to receive payments through his gateway VX Gateway..
I know the following:
http://www.triplematch.com/bo/listener/vxgateway.cfm

http://www.triplematch.com/bo/index.cfm

Merchant Id XXXXXXXXXXXXXXXXXXXXXXXXXX (removed for security)

Store Key  XXXXXXXXXXXXXXXXXXXXXXXXXXXXX  (removed for security)

In the new versions of Virtuemart I do not know where to put this info so it will process. 
How do I set up this new gateway?
Your help will be greatly appreciated.