Never got a chance to work with webservices like this, as per my understanding ( I may be wrong) I think this is as similar as regular webservice with only difference that it is not exposed to the outside worlds instead verified users only. I suspect this should work with QTP, have you tried with the authentication while connecting to webservice,
else see if this helps - https://www.learnqtp.com/web-services-an...ces-addin/
else see if this helps - https://www.learnqtp.com/web-services-an...ces-addin/