Communication Fault on calling a custom BO web service integration

Hi Experts,

While calling a custom BO webservice integration, I receive the following error:

"SOAP:1,048 SRT: HTTP error: ("HTTP Code 401: Unauthorized - Details see in error log of transaction SRTUTIL")"

I double checked for authorization view of the web service being called, it is in place; has been assigned to the desired WC and has also been assigned to the user that I am using for testing (a business user).

While testing the WS in SOAPUI, I get the following error:

"myxxxxxx.crm.ondemand.com:443 requires authentication with the realm 'SAP NetWeaver Application Server [KUM/050][alias]'"

For the above error, I referred this thread: http://scn.sap.com/thread/2033502

But the steps being mentioned here to resolve the issue, have already been performed.

Any idea on what's going wrong here? Please help !

Regards

Shruti