Credit card processing through First Data Global Gateway Web Service API

[DQ]

Hello,
  Is it possible to support credit card processing through First Data's Global Gateway API? First Data is word largest credit card processor and they have published their API with sample code in multiple languages including C#.  It is a HTTPS/XML and SOAP based request/response.

They do allow developer/demo account for testing.

http://www.freeglobalgateway.com/product-API.html

Web Service: http://www.firstdata.com/downloads/marketing-merchant/fdgg-web-service-api-v3.pdf

Sample C#/.NET Code: https://www.firstdata.com/downloads/customerservice/linkpointapi_c_net.zip