Updating A Task

I've gotten my PHP code to update persons, enterprises, and
appointments.  But updating tasks seems strange.  If I pass
person.updateJob two parameters - 1 a person document and 2 a task
document - I either get no change to the task or a new task created
equal to the contents of the modified task object passed to the method.

Anyone performed a job-update from PHP?
----
$_person = $_personManager->getById($this->server->getCurrentActorId());
$_response = $this->server->rpc_call('person.updateJob',
                                     array($_person->getDocument(),
                                           $_task->getDocument()));

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