Which Eclipse plugin are you using? By default, we still recommend people to use the existing BPMN2 editor that is provided in the Drools Eclipse plugin and integrates with the jBPM Eclipse plugin. This exposes the properties you mentioned for human tasks.
The new BPMN2 editor also allows you to specify this data but it is using a different format. The reason we still recommend people to use the old tooling is that at this point you can still only specify this at a rather low level, using low-level BPMN2 constructs like ioSpecification, peopleAssigment, etc. You need detailed knowledge of the BPMN2 specification to be able to specify all this. We're working on offering higher-level editors for all the supported BPMN2 node types, so that the business user can just specify actorId as a simple property and input / output mapping using a graphical UI. This should be available by the next release.
Kris