Automating HTTP Authentication using ASP.NET and MS Exchange 2003

[thewulf]

I'm currently building an application which will contain a link to MS
Exchange 2003. We'd like the user to the able to click the link and
automatically be logged in to MS Exchange 2003 using the web interface
but without asking them to retype their authentication information in
the popup box.

We've tried the classic http://user:password@server/exchange but this
comes back with ann "Invalid Syntax Error" in the web browser (IE6).

Any suggestions? I was thinking along the lines of making an ASP.NET
page redirect the request to the exchange server while adding the
authentication information in the HTTP headers but I'm not sure if/how
this would work.

Thanks,

-- Marc