Appears Swift Sound IVM and Sipme DID are not compatible. IVM appears to work but OGM cannot be heard, (Correct file is playing). However you can leave a message if you can correctly guess when the OGM has finished.
Works if dial in through a Sipbroker dial in gateway.
BBPGlobal works OK using their dial in number then extension number. (GSM Codec).
If anybody can enlighten me as to how I may be able to get it to work I would be grateful.