[HELP]: Implement PUBLISH (for presence) on behalf of phones

Hi Asterisk Gurus,

I have few IP phones registering to my Asterisk proxy. These in-turn will register as trunks to an external SIP proxy. There is an external Presence server to which these IP phones need to send their presence information to. But unfortunately, these phones do not support these SIP based presence methods like PUBLISH or SUBSCRIBE.

Adding this functionality in the phones is not an option. In that case, is it possible to provide this presence support in Asterisk on behalf of these phones? Asterisk should send PUBLISH with appropriate status to the presence server after registering to external proxy, in-call, un-register etc on behalf of the phones.

Is this do-able on Asterisk 1.4?

Thanks in advance

Chaitra

(Hope this is the correct forum for this post)