[Rivet] converting 2D histogram from ROOT to AIDA file

[Roman Lysak]

   Dear Rivet authors,

I'm working on Rivet implementation of an analysis which creates 2D 
histogram and need to convert data histograms from .root to .aida file.
I know one can convert 1D histograms (of graphs) from ROOT file into 
AIDA file by combination of 'root2flat' and 'flat2aida'.
As far as I understand, root2flat is not working for 2D histograms.
Do you know about some other tools (even unofficial) which would be able 
to do such conversion for 2D histograms?

Thanks a lot,
   Roman