Error in RatesCurveGroupDefinition.bindTimeSeries

Hi ,
My RatesCurveGroupDefinition has one user supplied curve and one definition. The RatesCurveGroupDefinition.bindTimeSeries(…) throws a nullpointer error when called with the user supplied curve since it does not have a CurveDefinition:

CurveName name = entry.getCurveName();
CurveDefinition curveDef = curveDefinitionsByName.get(name);

I am using the user supplied function to calculate the trades at the nodes.

Is this expected behaviour?
Thanks in advance,
Oyvind