I googled a lot to find out the smtp settings for mobily connect, but seems the tunnel is long as I haven't seen the light yet!
But the googling took me to this page where a workaround is describe and it works like a charm. The stunnel.conf I used is different than the one described in the page. I used the following:
accept = 25
connect = smtp.gmail.com:465
Please note to keep the
client=yesline at the very beginning of the .conf file.