I have a bpmn file with the following UserTask:

<userTask id="3" name="User Task">
<incoming>4</incoming>
<outgoing>6</outgoing>
<potentialOwner id="gruppeManagement">
<resourceAssignmentExpression>
<formalExpression>GruppeManagement</formalExpression> or
<formalExpression><![CDATA[GruppeManagement]]></formalExpression>
</resourceAssignmentExpression>
</potentialOwner>
</userTask>

When I copy it to Eclipse and open it with the Camunda Modeler it hasn't the "GruppeManagement" in the Candidate Groups Textfield on the Properties Tab.
Before the Camunda BPM Release I used the Activiti-Modeler which recognizes the <potentialOwner> and saves it as attribute on the userTask node as followed:

<userTask id="3" name="User Task" activiti:candidateGroups="GruppeManagement">