Chan_mobile and dtmf problem

Hi guys,

my chan_mobile config works perfectly for calls.
But I tied to make some application and using Read to get DTMF input.

Unfortunately Asterik doesn’t get any DTMF signals.
(if i connect the call to sip phone and start pressing keys on mobile - i can hear dtmf tones)

I use:

-Asterisk & Asterisk addons from head
-Sony Ericsson 800i

anybody has soluion for it?