asterisk users - Feb 2005 - DTMF outbound problem with ata 186

Hi

  This bug is really crazy, please help me

In the follow scenary

ATA-186 -> SIP -> Asterisk -> SIP ->  ATA 186 :

No DTMF gets through *  in outbound mode,

 Sip conf

[204]
 type=friend
username=204
secret=somesecretpassword
host=dynamic
canreinvite=no
; The follow line don't work
dtmfmode=rfc2833
nat=1