POSSIBLE
Hi, I am a Full stack developer in Microsoft technologies.
I guess you are using a custom class which builds a soap Request and make a http request to an external payment gateway. While doing so you are facing issues.
How I go about solving this issues is, I will need access to the test payment gateway, and along with the sample request.
I will modify your code so that it works as per the specifications and you get successful response.
My area of expertise is web application development, web services (SOAP & RESTFul), Sql Server as back end (through stored procedures).
I have 6 plus years of experience as a full time software developer.
Kindly contact me, lets discuss your requirements.