asterisk users - Oct 2006 - snom 360 - how to make record button working ?

Hi,

I'd like to make record button working on snom 320/360 + asterisk.

As I learned from wireshark output,  the phone produces SIP info
message "Record: on", while record button pressed.

Can anybody give me an advice, how to teach asterisk to understand
that SIP info message and start recording ?

TIA
noro