parameters to execute R script

I would like to know if it is not possible to develop such a version of the execute R script, to which it would be possible input not only input data, but also some parameters of the model. E.g. when I am using for instance random forests for regression it will be helpfull assign to execute script also some parameters as number of trees or mtry parameter. Exactly as with "normal" RapidMiner operators with parameters (e.g. C for SVM etc.). When this will be possible I think that door will be open also do some parameters optimisation for processes which are based on R scripts... Or is there some way to do this with existing version of this operator?
Thanks,
Milan