[Asterisk-Users] SIP domain in Asterisk

[Joao Pereira]

Hello to all
Can someone tell me if its possible to implement a SIP domain with 
Asterisk (im trying with Asterisk at Home).
With a SIP domain I mean:
-users having URIs with name at domain.pt ( instead of number at domain.pt )
-being able to reach our users anywhere in the world with SIP URIs (and 
the help of SRV records)
-the possibility of dialing name at otherdomain.pt and route the calls 
through the Internet

Can this be done?

Thanks
Joao Pereira