After Update to 4.0.7 on Soundstation IP6000 DTMF not work

Hi, 

I have made update on my phone Soundstation IP6000, but DTMF still not working, i opened sip file and check rfc2976 is 1 like on the example (http://community.polycom.com/t5/VoIP/FAQ-Phone-unable-to-send-DTMF-to-an-IVR-system-or-how-to/td-p/4237)

voIpProt.SIP.dtmfViaSignaling.rfc2976="1"

Can somehow help me ? 

Sincerely