Hello,
I am very upset with your first line when you mentioned you hate activiti. Even if you have to drive a Ferrari or a Merc, you should first learn how to drive and then you will enjoy it. You just cant say I hate Ferrari or Merc just because I don't know how to drive.
Anyways, Activiti is simple. User guide is very helpful if you get your basiscs right. I would refer Activiti 5.x business process management by Irshad Mansuri and Zakir Laliwala. I believe that book would help you get started. Refer to Activiti in Action by Tijs Rademakers once you get the basics right.
Coming to your question. You need to have your inbox developed by yourself and do not use activiti explorer for showing up your custom JSP when you set the form key. It just wont work because it was not developed that way. And when you open up a task from the inbox you've implemented, you can just pass the task id and get the form variables. and based on the form key value, you can open up a different UI/jsp and show the details.
