Outlook/Hotmail PROPFIND problem

I'm having trouble with some clients being unable to get their Hotmail
mail from within Outlook Express.
I searched the archives and found out why this was (Outlook includes a
PROPFIND Header in the request which Squid doesn't handle).

I've tried to work around it with the following proxy.pac file:

   function FindProxyForURL(url, host)
   {
        if ( shExpMatch(url, "*msn.com*"))
                return "DIRECT";
        if ( shExpMatch(url, "*hotmail*"))
                return "DIRECT";
        if (isPlainHostName(host))
                return "DIRECT";
        else
        return "PROXY 129.142.30.101:3128; DIRECT";
   }

It doesn't seem to solve the problem though (even after restarting the
Outlook machines).
So the question goes: Is there a patch that makes Squid capable of
serving/proxying these (WebDAV?) requests?

I'm running Squid/2.2.STABLE5 on a FreeBSD-3.3 machine. It is going to
be proxying a full building with many a phb who are not easily convinced
that Hotmail and Outlook in of itself is a bad idea altogether.
Furthermore we are planning on making it a transparent cache next week,
and I'd like to avoid the pain of dealing with Outlook/Hotmail users
:-).

-- 
Hroi Sigurdsson
hroi@existential.dk