Problem with dependencies

[Stefan]

Hi automake list!

I'm trying to write a Makefile(.am) to make pdf plots from R scripts. Hence the 
plot is depending on the script and the data. What I tried is:

SUFFIXES = .R .data .pdf

.R
        make R script executable

.R.pdf:
        Do stuff

.data.pdf:
        Do the same stuff as for .R

in the Makefile.am (plus a bit of other settings).
For changes in the R-script, the pdfs are updated, but not if I change 
something in the data.
What am I doing wrong, here?

greetings,

Stefan