We have WSDL files not the URL's and have QTP scripts for Webservices.
So for WSDL reference, we are mapping to local drive.
But our goal is to add all these WSDL files to Test Resources in ALM and map that to QTP script instead of local drive.
Have you checked the OTA-API documentation for test resources? However, you might be better off upgrading to UFT and seeing what it supports. While the service test add-in for QTP can be used with older versions of UFT it might have been dropped from the latest version.
Up to ALM 11.52 You can store WSDL's in the resources module once you added the Service Test Manager extension.
I'm not sure about ALM 12.2, but selecting "Add-ins" from the Help menu will lead you to the information.