[Rivet] Question concerning histograms

[Martin Stoll]

Dear Rivet,

I'm writing a Rivet analysis right now and want to ask you something 
about histograms.
I want to fill AIDA::IHistogram1D* _histo (which has non-uniformly 
distributed bins) with data, so for each bin I call fill and pass the 
desired value as weight. But it seems I have to somehow scale the value 
with the bin width instead:
_histo->fill( _histo->binMean(i), myValue * _histo->axis().binWidth(i) )
which seems awkward, but does produce the right plot.

Is there a better way to create this kind of histogram? (In fact I want 
to fill my histogram with the ratio of the entries of two other ones.)

Thanks a lot,
Martin