[Users] Problems with DNS.

[nick]

I'm trying to get my machine ready to work externally, with public Ip 
addresses.

I believe I've got all the pieces ready for the domain.

I have the PTR records published for my server's public IP address. I 
have the .sip_.udp.mobilia.it. 0 0 5060 sipserver.mobilia.it. record (I 
tried it with and without the .mobilia.it added to the udp) published, I 
tell the server to listen on the IP addresses which maps it's name in 
DNS, I have a line after listen :
alias="mobilia.it" (I've tried both FQDN and this)

I've exported the domain both as the command export 
SIP_DOMAIN="mobilia.it" and in the openserctlrc (does it need to be the 
FQDN or just the domain, again, neither seem to make a difference..)

however, I still can't get the machine to believe that it is actually 
responsible for this domain.

When I register I have errors along this line: (it registers, obviously, 
but the logic is wrong, since he thinks the user is coming from another 
domain).

  grep_sock_info - checking if host==us: 10==13 &&  [mobilia.it] == 
[89.202.252.16]
Nov  3 10:13:34 sipserver /usr/local/sbin/openser[3193]: grep_sock_info 
- checking if port 5060 matches port 5060
Nov  3 10:13:34 sipserver /usr/local/sbin/openser[3193]: grep_sock_info 
- checking if host==us: 10==13 &&  [mobilia.it] == [89.202.252.16]
Nov  3 10:13:34 sipserver /usr/local/sbin/openser[3193]: grep_sock_info 
- checking if port 5060 matches port 5060

Can anyone venture a guess as to what I might be missing???