OK; I think I got it.
I used $_POST[myHiddenField] as trigger and it triggers if not empty, so this works.
do I need to take care for something else?
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.