Hardware conference in SRST mode is not working for 7841 IP phone

[anilkumar.cisco]

Hello Team,

Enclose is the configuration, kindly open in Wordpad.

During SRST mode,

Hardware conferencing is not working with SIP 7841 or 3905 IP Phones..

whereas conferencing is working perfectly with 7841 phone because it is working internal bridge..

My requirement is to made them use dsp resource, which is not happening here..

for SCCP phone, hardware conferencing is working perfectly without any issue.

Kindly advise urgently