[HELP]A complex DTMF problem with various asterisk, Routers

Can any one help me with this issue, or has any one had been through this:

Here’s an image of the Network that I have:

The problem is:

Every time I’m trying to send DTMF tones to the remote PBX’s, it doesn’t work at all. The DTMF is originating on a Polycom 301, GrandStream BT101, Soyo, and X-pro softphone; all of them using rfc2833

I tried joining the Asterisk’s with Iax, buy it didn’t work, and then I tried using sip, and after a lot of work, it worked but using G711ulaw, but as you can imagine there’s a lot of traffic, and I cannot left that codec, I need to use G729 or G723.

All the Addpacs are using g723 and g729 with DTMF=rcf2833, take a look:

! Voip peer configuration.
dial-peer voice 1000 voip
destination-pattern …
session target sip-server
session protocol sip
dtmf-relay rtp-2833
no vad

Any ideas??