Pidgin ntlmaps gtalk behind isa proxy

I need to connect gtalk. Because support team of vendor companies using gtalk.
Nntlmaps; proxy software that allows you to authenticate via an MS Proxy Server

Install ntlmaps
# sudo apt-get install ntlmaps

configure ntlmaps
# vi /etc/ntlmaps/server.cfg

PARENT_PROXY: your isa proxy ip adress
PARENT_PROXY_PORT: you isa proxy port
NT_DOMAIN: domainname
USER: nt username
PASSWORD: nt password
LISTEN_PORT:5865 (ntlmaps listen port)

Pidgin --> accounts --> manage accounts --> modify --> advanced
check force old ssl clear others
connect port: 443
connect server: talk.google.com

In proxy tab
Proxy type: http
Host: 127.0.0.1
Port: 5865 (ntlmaps port)
Username: nt username
password : nt password