If the MFIM is on version 5.5 or 5.6 or 6.0 Software, then port fwd
UDP 5060 to the MFIM as this controls the SIP setup
UDP 7000 - 7015, UDP 7100 - 7115, UDP 7300 - 7315 to the MFIM as these are the Audio port for the MFIM VoIP
then UDP 6000 - 6047, UDP 8000 - 8047 and UDP 9000 - 9047 to the VoIM24 as these are the Audio ports for the VoIM
Then in
PGM 132 - Sequence number of the MFIM VoIP - input the Firewall IP Address which will be your Fixed Public WAN address
PGM 132 - Sequence number of the VoIM24 - input the Router IP Address (Gateway IP Address), and the Firewall IP Address which will be you Fixed Public WAN address
Regards
Steve