Remember that CUE only supports G.711. So, you need to make sure you have a Dial-Peer for CUE with G711 and I believe a 3rd Dial-Peer pointing to the loopback for the CUE. This way, the call comes in as G729 (it is not negotiated because the trunk is g729 only), will match the Loopback dial-peer, loop through the interface and come back in and match the G711 CUE Dial-Peer and invoke a transcoder and forward the call to VM.
Hope that helps. Scott
