1. I’m using user “siebel” to do all the below, it’s not recommended to use “root”.
2. Download the installation files from Siebe’s image and upload it to the server
3. decompress the file and navigate to: enu->unix
4. There is only one file there, change its permission to be executable to run it (chmod +x NetChartxxxxxx.bin)
5. Run the installer, there is a graphical mode and console mode, I prefer the console mode which takes much less bandwidth and executes much faster, to do this run “./NetChartsServerxxxxx -i console”
6. Proceed normally with the setup, all what you need to do is choose the installation location and the port (if you need a port other than the default one, which is 8001)
7. It will prompt you to start it up for you after installation is complete, doesn’t matter
8. Navigate  to “/siebel/netcharts/Server/root/projects”, where “/siebel/netcharts” is my installation directory, and create a directory there named “Siebel.chart”: “mkdir Siebel.chart”
9. go to this new folder and create a text file using the “vi” editor and type “CDL” inside it (without the quotes), then save the file as “Siebel.cdx”
10. Restart the Netcharts server by navigating to “/siebel/netcharts/Server/bin” and running “./NetChartsServerControl stop” and then “./NetChartsServerControl start”
11. The installation is now done, all what’s remaining is configuring Siebel to properly connect to the server
12. Access the siebel URL and login as “sadmin”, navigate to “Administration – Server Configuration->Enterprises ->Profile Configuration, query for “Server Datasource”
13. In the profile parameters, change the value of the “Chart Server” to server:port, for example, in my case, where I installed the charts server on the same machine, I used “localhost:8001”
14. The tricky part, which is not properly documented in the Bookshelf, is that you MUST change the parameter “Chart Image Format” to “jpg”, might work if you choose another extension, but it doesn’t default to any value, as stated in the Siebel 8 Bookshelf “Set the value of the parameter DSChartImageFormat to png, jpg, or gif. The default is png.”
15. Restart the Siebel Server, and you’re ready to go.

Hope the above was clear enough.

Credit goes to my colleague at IBM: Ahmed Kishk, who brought my attention to the DSChartImageFormat parameter