Hi Marcel,
At this moment, jBPM4 does not support ehcache configuration for hibernate. The configuration you have found is included by jBPM-4.0-Alpha2. It is removed by some reason(Maybe). There is a huge change from jBPM-4.0-alpha2 to jBPM-4.3, so I don't think it could be used in jBPM-4.3 directly.
The configuration for jBPM-4.0-alpha2 is in the attach, maybe you could let it be used in jBPM-4.3.
Best regards.