What is the server name secret for connecting FM12 and SharePoint 10?

All attempts to connect FM12 and SharePoint 10 result in this message: "The request failed with HTTP status 404: Not Found."

In FM12, I opened Connection Manager, selected SharePoint, and entered:

• connection name
• server and site address
• user name
• password

The SharePoint site displays successfully when I enter the server and site address in a browser, but SharePoint and FM aren't talking to each other for some reason.

I tried entering all possible versions of "server and site address" in the FM Connection Manager with no success.

http://servername/sites/xyzzy

http://servername/sites/

http://servername/sites

http://servername/

http://servername

I added the port number at the end of the server name as suggested in the tip below the server field "(e.g. http://server:port)" and got a "status 400: Bad Request" message.

What's the secret to getting past this step?

Thank you very much for your help.  I would love to get on with the rest of the process!

Mary