Does Presence information work with HTTP proxy and Windows Messenger v5?

Has anyone used Windows Messenger V5 with an HTTP
Proxy ? Did it work OK ? In Windows
Messenger...tools...options...connections...
use a Proxy is checked on and type = HTTP proxy.
Will Windows Messenger use HTTP even if native port is
available ?
Does the Contacts' presence information work
correctly ?
How often is the presence information updated via
HTTP ?
Example: If a contact Logs off .NET Messenger Service at
4:00 PM, when will someone using HTTP-proxy see that the
contact is Offline ?
Which brand of proxy server are you using ?
Thanks.