See:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnfoxgen8/html/vfp8_taskpanemgr.asp

I looked a little further just to see how they are accessing it. The code is in the xsource.zip. They parse it from the cURL in the BeforeNavigate2 event of the browser control and set CANCEL = .T. if found to prevent the default navigation.

You could easily do the same thing.