asterisk users - Nov 2010 - multiple devices wants to call through single peer (trunking)

Hi list,

how can I set up an peer, so that behind one IP (NAT) multiple devices 
can access to this single peer to make outbound calls.
Some of these multiple devices will be SIP phones and these SIP phones 
are trying to make registrations to this peer.

best regards
Thomas

Dear All,

This question is related to an old zaptel version (1.2.14) that I'm using
for specific reasons on one of the machines in combination with Sangoma cards.
The version of zaptel/asterisk/libpri cannot be changed :-). Even though this is
an old version, I still hope somebody will be kind enough to help me a bit.

The following problem came out of the blue: whenever I stop Sangoma drivers
(command "wanpipe stop") the /dev/zap/channel /dev/zap/pseudo
/dev/zap/timer and /dev/zap/transcode devices disappear. Executing command
"ls /dev/zap" returns "ctl" only.

Starting the drivers and executing "ztcfg -vvv" doesn't help.
Asterisk will not start up again unless machine is rebooted. Asterisk will
complain with "/dev/zap/channel: No such file or directory" during
zaptel load.

Everything boots fine though if I restart the whole computer. So I am guessing
something trivial must be wrong. UDEV settings, zapata.conf, zaptel.conf are
correct.

Regards,
Alex

P.s: I have already contacted Sangoma support, but so far we didn't find any
solution yet.