Is there a naming convention for the XMl file posted to a typical ReST server for authentication?

Alberto Nocon

Anyone know if there's a naming convention for the XML document that is posted for authentication to a typical ReST service? I'm trying to authenticate to a US Courts test ReST server, but always get a canned 200 status and same JSON regardless of what's in my XML post file. I'm not getting the technical information I need from them to clarify their authentication requirements so I'm trying some things out until I get the information I need.