I've tried clone through MS ISA proxy using usual URL format for proxy setting (http://username:password@proxy.server), and fail with message:

server says: 407 Proxy Authentication Required ( The ISA Server requires authorization to fulfill the request. Access to the Web Proxy service is denied. )

I've also tried DOMAIN\username as possible format of supplying username. But result the same.

Do fossil supports NTLM authorization for proxies?

Many thanks in advance!