I am trying to send message with collaboration system between users programmatically. I wrote a common module like this;

Procedure DirectMessage(ConversationID,Msg) Export
   id = new CollaborationSystemConversationID(ConversationID);
   Message = CollaborationSystem.CreateMessage(ConversationID);
   Message.Text = Msg;

If I get user id from collaboration system interface with asking link, it works for me. But other users must do same thing in their interface.
I have a problem to get user id of conversation. Is there anyone knows how get user id?