asterisk users - Dec 2009 - Setting the Request URI In registration

Hi,
I have just installed asterisk, I want to send registration request to
192.168.4.3:6090 and the domain should be test1.net
I have added the following line to sip.conf

register => 897987 at test1.net:pazzwrd:897987 at 192.168.4.3:6090

now the problem  is that the SIP Request is appearing as 192.168.4.3,
while I need it to be test1.net
How can I set that ? I am able to register with the provider easily
using x-lite/phoner

Thanks
AK