How to register aggregation convergence criterion to bulk iteration in scala API?

[Fridtjof Sander]

Hi,

I want to register a custom aggregation convergence criterion to a bulk 
iteration and I want to use the scala API.
It appears to me that this is not possible at the moment, right?
The AggregatorRegistry is exposed by IterativeDataSet.java, which is 
hidden by DataSet.scala:

  def iterate(maxIterations: Int)(stepFunction: (DataSet[T]) => 
DataSet[T]): DataSet[T] = {
    val iterativeSet =
      new IterativeDataSet[T](
        javaSet.getExecutionEnvironment,
        javaSet.getType,
        javaSet,
        maxIterations)

    val resultSet = stepFunction(wrap(iterativeSet))
    val result = iterativeSet.closeWith(resultSet.javaSet)
    wrap(result)
  }

I am aware of the iterateWithTermination-possibility and it's a 
work-around for me, but I guess the aggregated convergence criterion 
would be more efficient.
Am I missing something?

Best,
Fridtjof