The CMS Call Bridge only operates in SIP - the H.323 Gateway is really only for inbound H.323 traffic conversion, and not outbound.
As the H.323 gateway is destined to disappear in a future release of CMS, if you have other ways of handling the H.323 to SIP conversion (ie, it's recommended that you use the Expressway or VCS solution) then that would be a better option than relying on CMS to do it.
An option for your IP address dialling (eg dialling 1.2.3.4) could be to dial endpoint@1.2.3.4 as this looks to the system as a valid sip URI which just 1.2.3.4 isn't. Most endpoints will accept a call using that H.323 Annex O format address.
Wayne
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