[asterisk-users] Disable transfer on all calls

[bee.beeep at gmail.com]

Hi folks,

I have some asterisk 1.2 box with self-made billing, and I need to 
disable call transfer on all calls and directions.
I turned it off in features.conf and there is no 'tT' option in all my 
Dial() commands, but users still able to transfer call using "transfer" 
function in ip of softphones (AFAIK this function uses SIP method 
REFER), so this transfers are hard to trace in CDR  and my users can 
make a free call using trick with transfer:)

I've googled it, but didn't find anything about my problem :(

Thanks,

Danila