Hooking a template to an action in RT 3.4?

Hi all,

I want to use a template I found on the wiki [1] to the actions in the
upper right of the ticket detail view (Ticket/Display.html). By
overriding Ticket/Elements/Tabs, I am able to create a new link in the
ticket view, but I am unable to figure out how to create an action which
Ticket/Update.html would accept and invoke my template.

All tips & links appreciated :slight_smile:

[1] AddTicketHistoryToMail - Request Tracker Wiki