[BioC] boxplot of subset of PLMset

[Rebecca tagett]

Hello!
I am trying to do a boxplot using a subset of a PLMset (just certain
boxes). Without trying to subset (3 lines of code below), it works just
fine. (It is the same thing as NUSE)

	# THIS IS OK
	fplm <- fitPLM(myAffyBatch)
	ss <- boxplot(fplm)  
	bxp(ss)

How can I get a subset of the PLMset ? Here are 2 things that I tried,
using the subset argument in boxplot, which did not work (where
cels4Plot is a vector containing the CEL file names):

ss <- boxplot(fplm, 
subset = sampleNames(fplm at phenoData)== cels4Plot)

ss <- boxplot(fplm,
subset = which(sampleNames(fplm at phenoData) %in% cels4Plot))

Thanks for your help!