One of possible solution to that would be to use following method from TaskClient:
public void getTaskByWorkItemId(long workItemId, GetTaskResponseHandler responseHandler)
if you can include work item id while sending the link. You could get work item id with onExit-script of the human task - set it as process variable.
Then use that work item id to query for task.
If that is not good for your case you can always use the generic query method from TaskClient.
HTH