httplib/DAV: How to respond to "WWW-Authenticate: NTLM" ?

[robert]

In a DAV scheme with PROPFIND or GET (PROPFIND /test/ HTTP/1.1)  and 
Basic AUTH to a MS SharePoint over https server (AUTH required), he 
responds 'WWW-Authenticate: NTLM' only:

reply: 'HTTP/1.1 401 Unauthorized\r\n'
header: Content-Length: 1656
header: Content-Type: text/html
header: Server: Microsoft-IIS/6.0
header: WWW-Authenticate: NTLM
header: X-Powered-By: ASP.NET
header: MicrosoftSharePointTeamServices: 6.0.2.6568
header: Date: Thu, 12 Oct 2006 12:27:42 GMT


I simply try repeatedly the same request with Basic Auth header again => 
The same response requesting 'header: WWW-Authenticate: NTLM' again.

But then after an unsuccessful test on a really new connection (.close() 
, .request()) he accepts the Basic AUTH immediately.

* What is this?
* Is this a legal/known way to respond to a NTLM AUTH request by 
.close() and reconnect with Basic Auth?
* Is there a Python function out there to do real NTLM authentication?.. 
and is this recommended to dig into Microsofty HTTP protocols ?


-robert