[SR-Users] Kamailio and Free switch - multi tenant

Hi all, First time poster here. I had a freeswitch installation configured to allow users to register with different domains e.g. tenant1.mydomain.com tenant2.mydomain.com .. tenantN.my domain.com This worked fine. Users were able to call extensions in their own domain and access their voicemail. All tenants/domains shared the same diaplan (default). I followed the great tutorial at http://kb.asipto.com/freeswitch:kamailio-3.3.x-freeswitch-1.2.x-sbc I now have my users (using different domains as above) registering to Kamailio. It was a little tricky but I can now place calls between users on the same domain. For some reason the variable ${domain_name} (from the tutorial) seems to be empty so I had to replace it with a channel variable (I'm not in front of my dialplan now but it was something like ${sip_from_domain}. Was this the right thing to do? Why does the domain_name variable not populate with the domain of the user making the call? Another issue I have is to do with usernames. I want my users to have alphanumeric usernames e.g. user1(a)tenant1.example.com user2(a)tenant1.example.com But I'd also like them to be able to have an associated extension and mailbox. E.g. user1 may be extension 1001 and mailbox 1001 user2 may be extension 1002 and mailbox 1002. In Kamailio I've handled this by using aliasdb. So user1.tenant1.example.com has an alias of 1001.tenant1.example.com Scenario: User2 dials 1001. Kamailio evaluates this and determines we want user1. It passes the call to FS with a $rU of user1. However, even though user1 is registered and online...the call fails and diverts to voicemail - any ideas? Also I had to hack the above so that after the alias db lookup Kamailio sends an $rU of 1001@tenant1... If anyone has got FS and Kamailio running with multiple domains I would really love some feedback on routing and dialplan configuration. Thanks so much in advance, CD