TFS - Transport error - 401 Error: Unauthorized

I'm a new user to WebStorm 7 and need source code integration with a TFS 2012 server running on Windows 2008 R2 SP1 machine.

I have installed WebStorm 7 on  a CentOS 6 machine. When setting up the TFS plugin to access the TFS server using the 'Alternate Auth'  I get "Transport error - 401 Error: Unauthorized."

The TFS server event viewer has no record of the event.

The same setup from a WebStorm 7 on  a Windows 2008 machine works fine and  I have no problem accessing TFS from the CentOS machine when using Eclipse

However I really need to have my app developed and working on a CentOS server.

Any insights?

Thanks so much
Patrick