Oscam is not in the downloads because there's no active development for Enigma1 anymore
Kod:
http://openpli.org/forums/topic/25603-dm500s-as-server-best-softcam-options/?view=findpost&p=301687
Kod:
There's nothing to install, you have to manually set it up.

- put the oscam binary in /var/bin
- create a file called 'oscam' in /var/etc/plimgr/cams, put a version number in the file
- create a startup script in /var/etc/plimgr/scripts (take one of the others as an example)
- update /var/etc/plimgr/plimgr.conf so that it contains <emu>oscam</emu>

Now oscam should be visible on the box in the softcam menu, and should be started when you start the box. 
On my box the oscam config files are in /var/tuxbox/config.
OScam - Dreambox DM500/500S & DBox2
Kod:
http://download.oscam.cc/index.php?&direction=0&order=mod&directory=1.20_TRUNK/powerpc-tuxbox-old