Hello,
The first thing I have to say about the number@ip dial plan, is that the expressway does not make any DNS resolution. The call will not go out to the internet via the the DNS zone as a regular SIP URI, instead it goes out via the default zone, it make a direct connection to the number@ip. Also, the call will do Interworking from SIP to H323, so the far end will most likely be contacted via a H323 leg.
The Dial Plan configuration needs to be set as follows in each server.
Exp-C: Calls to unknown IP addresses "Indirect"
EXP-E: Calls to unknown IP addresses "Direct"
In the Exp-C, you need to set up a search rule as in the attached picture, considering that you may have other search rules, you may need to change priority of the search rule. In the Exp-E you will not need to create a search rule, since no search rule will be considered for this type of call.
I imagine you will make calls to a conference bridge sitting in the internet, so it depends on the bridge to accept the call you try to make, since the conference may or may not exists.
I hope this helps.
/Elias
