Any parameter you define in your BPMN2 should be accessible in the workitem. The wid is simply just to show some default paramters in the tooling support (Eclipse, Designer).
I think the problem may be here:
<dataInputAssociation>
<sourceRef>boolResult</sourceRef>
<targetRef>_3_boolResultInput</targetRef>
</dataInputAssociation>
You seem to be mapping boolResult to itself?
Hope this helps.