[asterisk-users] atxfer not working

[gincantalupo]

Hi,
I cannot get attended working on my Asterisk 1.2.9.1 during an inbound 
call via an ISDN card to a Snom SIP phone.
The called party is not able to transfer even if :

1 - atxfer is enabled (set to *7) in in features.conf
2 - the dial option is set to value 't'
3 - I see * and then 7 on Asterisk CLI when debug is set to DTMF

Asterisk gets the right sequence from Snom phone (CLI does not lie) but 
for some reason Asterisk is not transferring the call while the caller 
keeps on speaking with the called party.

Is there anybody who knows what is going wrong?

TIA

Giorgio Incantalupo