CISCO 7906G and Paging with Asterisk

I need help on how setup Cisco 7906G to receive paging from Asterisk.

On other SIP phones I used to do that by setting the parameter “Allow Auto Answer by Call-Info:” to yes in the phone configuration then set the SIP header in Asterisk dialplan with :

exten => *7778,1,SipAddHeader(Call-Info: ;answer-after=0)

Any idea how to achieve similar setup with Cisco 7906G IP Phones?