IP Station Duo UC4.0.12.xx, how to add "tone tone.dtmf.rfc2833Payload="127"

We use IP Station Duo (SIP), registered to Cisco Call Manger, it got issue with external DTMF IVR.

I found detail from this knowledgebase

http://community.polycom.com/t5/VoIP/FAQ-Phone-unable-to-send-DTMF-to-an-IVR-system-or-how-to/td-p/4237

I have been up load the "dtmf_payload_127.cfg" still did not working, or which configuration path that I can do revise ?

config_files.cfg, web.cfg,devices_settings.cfg or phone_local.cfg ?    

Cisco engineer checked on voice gateway and ask to change DTMF tone to be 127:

 <dtmf>  <tone tone.dtmf.rfc2833Payload="127"/> </dtmf>

Phone InformationPhone Model SoundStation Duo Part Number 3111-19000-001 Rev:H         UC Software Version 4.0.12.0926 BootROM Software Version 5.0.12.0033