Hi Manuel,
Now, jBPM 4 only records history for TaskActivity, StateActivity and DecisionActivity. If you want to trace the Automatic Activity's performance, the jBPM 4 didn't provide history datas for this. You have to store that information by yourself.
I think the aim of jBPM 4's history datas is used to tell how long a step had wait, not how long a program had cost