Apologies to all for the repeat post but I'm lookiing for a solution to this problem.
Old topic, but maybe you can provide an update on the solution you might have found. I'm having a similar issue.
Some details:
2 remote (home office) locations behind Cisco routers providing IPSec site to site VPN tunnels back to head office.
Phones calling head office can communicate correctly.
Phones calling remote location to other remote location, ring but have no voice
Thanks