sedwardson
We use a few things to thread emails to existing tickets. First and foremost is the References and In-Reply-To headers. Then if that doesn't match we try to decode the Message ID to see if it contains the Ticket ID User ID. If that doesn't match then as a last resort we try to look for the Ticket Number in the subject.
So if they didn't reply directly to an alert from the Ticket or a reply from the Agent then the only way is to add the Ticket Number in the Subject. It has to be in the format of #22-1234 or #1234.
Cheers.
