Using Jaconda with Google Apps for Domain
To allow your Google Apps accounts to chat outside the Google Talk, you have to add some domains' DNS records like you did it for Gmail.
You can check that this is your case by entering your domain
name here: http://www.process-one.net/en/imtrends/
If you see this, everything is ok and you don't have to do
anything:

Otherwise, you'll need to edit the domain's DNS Service (SRV) records as shown below.
Note: When updating your SRV records with the following information, make sure to replace yourdomain.com with your domain.
_xmpp-server._tcp.yourdomain.com. IN SRV 5 0 5269 xmpp-server.l.google.com.
_xmpp-server._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server1.l.google.com.
_xmpp-server._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server2.l.google.com.
_xmpp-server._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server3.l.google.com.
_xmpp-server._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server4.l.google.com.
_jabber._tcp.yourdomain.com. IN SRV 5 0 5269 xmpp-server.l.google.com.
_jabber._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server1.l.google.com.
_jabber._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server2.l.google.com.
_jabber._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server3.l.google.com.
_jabber._tcp.yourdomain.com. IN SRV 20 0 5269 xmpp-server4.l.google.com.
If you require assistance making these changes in your domain
host account, we suggest contacting your domain host.
Article about using Google Apps for Domain Google Talk
accounts
Screenshot from goDaddy:
Screenshot from MediaTemple: