openssh unix dev - Sep 2003 - SSH2: How can I forced the server(ssh2) to send messages to client?

Hi:
My ssh server  ( In ssh2 ) want to send messages to client ( putty ).
But I can't find way to do this.

I write below code :

packet_start( I_DONT_KNOW_WHICH_ID_TO_BE_USED );  <- ???
packet_put_cstring( "Some messages..." );
packet_send( );
packet_write_wait( );


In packet_start( ), Which ID must be used?
Or there is the other way?