compress(), zlib and FlateDecode filter in PDF stream

[jbv]

Hi there,

Has anybody succeeded in using the compress() function
on PDF data stream using the FlateDecode filter ?
According to both docs (PDF ref and Rev), both compress()
and FlateDecode are built around the public domain zlib
library, but I didn't manage to include compressed data
in a pdf file, nor to decompress any pdf data stream in
Rev...

Any idea ? Could there be some additional encryption in
the pdf data stream, or some additional parameter for the
FlateDecode filter (predictor) ?

Thanks,
JB