asterisk users - Sep 2005 - SIP, NAT and MySQL support (sipfriends)

Hi all,

I am new to asterisk and I can not find any detailed info on using SIP 
MySQL support (sipfriends) with clients behind NAT. I've heard that I 
have to patch chan_sip.c and Makefile to get it working.

I tried on voip-info.org but found no answer for my questions.

I found some answer on Digium mail list archive:
http://lists.digium.com/pipermail/asterisk-cvs/2004-January/000854.html
but I do not know for what version of Asterisk it is aplicable.

I hope you will help me a bit.
-- 
Jarek