I think your code-fragments didn't come through the was they should. Are you referring to the "owner" or the assignee?
The assignee can be set in XML using the activiti:assignee="…" attribute on the user task (or the BPMN-counterpart, see user guide). If you want to set the "owner", this can be done in a task-listener on the event="create", by calling delegateTask.setOwner(delegateTask.getExecution().getVariable("theVariableYouNeed")) or something similar…