Activating the 'Park' softkey via a SIP message on a Cisco phone

Asterisk Asterisk Endpoints
1

Hello,

I want to trigger the “Park” SoftKey on a Cisco phone via a SIP message. The reason for this is that I want to initiate parking through the Cisco phone to the PBX, rather than directly on Asterisk, because the Cisco phone wouldn’t be aware of the parking if done directly on the Asterisk.

I am using SIP firmware on the Cisco phone, not CUCM, but Asterisk.
How can I implement this to activate the “Park” function by sending a SIP message to the phone? Also, what do I need to configure on the phone, and how does the phone expect an XML message or SIP notification to trigger the SoftKey?

Just to clarify, I do not use CUCM.

Thanks in advance!