minfi package: plotBetasByType, GenomicRatioSet-clas

Question

[kawaguca]

I have the methylation data of human methylation450k.

The IDAT files were read with the minfi package. Then preprocessFunnorm(RGChannelSet) was done. I tried to plot the overall density distribution on beta values and that of the I and II probe types using the plotBetasByType function of the package. But the function can be used only for a MethylSet or a matrix. Is there a way to use the function on the GenomicRatioSet-class?

Thanks