[BioC] plotAffyRNAdeg x-axis length of RNA digestion plot

[Sue Jones]

I am using the plotAffyRNAdeg function from affy to create a RNA digestion 
plot. I use the following code

Data <- ReadAffy()
deg<-AffyRNAdeg(Data[,c(1,2,3,4)])
jpeg(file="RNA_digestion_plot.jpeg")
plotAffyRNAdeg(deg,col=c(1,2,3,4))
labels<-c("E2h rep 1", "E2h rep 2", "E2h rep 3", "E2h rep 4")
legend(5,6,labels,lty=1,col=c(1,2,3,4))
dev.off()

The problem I have is that the x-axis is too short (only extends 0-10) 
and the lines extend over the end. How do I extend the x-axis up to 15 as 
I have 13 probes?


Thanks

Sue Jones