Multi Domain Web Services steps?

I am trying to monitor our website and validate a test account can log in successfully.

The site uses Form Based authentication (not Basic or NTLM).   So I need to somehow POST the login credentials to another webservice and have the info sent back.

Problem is the authentication web service page is on a different URL domain.

Step 1: Navigate to http//:www.abc.com  and validate splash page

Step 2: "Get /login.aspx"  (takes me to http://www.abc.com/login.aspx)

Step 3:  POST User/Pass & *probably* cookie session info from Step 2 to https://idt.abc.com/authenticate

Step 4: Get the "login successfully" response from idt.abc.com and validate page

Seems once i create a Web Service can only define 1 domain (i.e. www.abc.com), so I have not way to make the secondary call to the webservice to authenticate that login..at the different domain idt.abc.com

Any way to do this with LogiMonitor Services?

Thanks