Help for own action needed

Hi,
I want to create a new ticket-related action which can be selected in the
topnav and which does something and finally creates an email to the
requestor. The “something” should be logged like a comment in the ticket
history and the email should be logged to like any other emails.

Step 1: I added a own action in

Callacks/MyCallbacks/Ticket/Elements/Tabs/Default

which works well. The link appears correct.
It points to an URI Ticket/Coupon.html

Step 2:
I copied Ticket/Update.html to Ticket/Coupon.html, removed all the form fields
I don’t need and added some others. The form looks Ok.

But now I get stucked: Searching in Update.html for the the code where the
"update" is done , but I dont see anything. Looked in autohandler, in
Interface::Web::Handler, nothing. Am I blind ?
So how does the workflow function ? Where does the action happen ?
And how can I link a template to build the outgoing e-mail with Coupon.html?

Greetings
Rolf Schaufelberger
E-Mail: rs@plusw.de