DOCBOOK-APPS: Difficulty with eps format

Probably this is only partialy related to docbook.
I would like to include an eps diagram in the PDF rendition of a 'book'.
But latex says 'unknown graphics extension .eps'. How can I correct this ?

I am using the DSSSL style sheets V1.70 and the packages
docbook-utils-0.6.6-1, jade-1.2.1-6, jadetex-2.20-6 and tetex-1.0.6-11 on a
linux system (RH 6.2).

Thanks,
Ekkehard