Thank you for your hint Maciej.
You are right I didn't implemented my own MessageEventSendTaskHelper.java. Now I have more options to trigger the message catch event.
The model above was a just simple example to check if message events work but it doesn't before.
With the Eclipse Bpmn 2.0 - plugin I have modelled 2 pools which I want to connect with the help of message events.
My intention: If the first process is at the end node it can throw a message event so the other can continue his steps after it catched the message event.