[Asterisk-Users] Routing NOTIFY SIP messages

[John J. Sawa]

Is it possible to send SIP NOTIFY messages to * users through asterisk 
through an external application? Does that external application have to 
be a registered * user in order to send the NOTIFY message to other 
users. I have tried sending unsolicited NOTIFY messages to * but the 
application receives a Method not Implemented back from *

Please advise as the best way to proceed, in order to have * route SIP 
NOTIFY messages from an external application.

Thank you, in advance. -John