Björn,
"are you talking about Mac OS X Tiger SERVER ?"
Yes
"I can not share the FaxServer in Server Admin because the modem called FaxServer isn´t listed at Printserver > Setup > queues. "
It is not for me either. I did not actually tell the server to share the fax. As I mentioned in the posts above, it appears to do that on its own. It appears that Server Admin > Print Services > allows you to see items in the fax queue but you cannot actually set up any of the details for the shared fax.
"In the Tiger client version there is a share this fax button in system preferences. "
I agree, there is a share button for the fax in the client 10.4 System Preferences > Fax and Print. As mentioned in previous posts it appears that ANY 10.4 machine can "serve" a fax. 10.4 Client can do it presumably by simply setting fax sharing on in system preferences.
"I can NOT see the FaxServer on any client in the print > fax panel. There are no shared printers and no shared faxes in the drop down menu."
Do you have printers that are shared by the server that you cannot see on the local subnet? If so your server may not be serving any Printers/Faxes.
Just for clarity, this is where I find things: At the client, in the print dialog box, under the printer pop up you will have "Shared printers >" as a sub menu ONLY IF the client can see shared printers. The same happens in the Fax dialog box for me. If I shut off print service on the server the shared sub menu does not appear.
Bottom line. I am not confident about what mechanism is controlling this...however, you seem to have the same appearance as I do as far as where the 10.4 SERVER's fax appears in Server Admin. With all of the playing around I did with this I am not sure when, but I definately performed a restart to clear things out. Try that. After I got this to work once, I deleted everything and redid the procedure as listed in earlier posts to make sure. In retrospect I may have had the same problem, no shared fax. Restarted server, waited for complete boot, restarted client and then the "shared fax" submenu was available on the client.
Another detail, now that I'm looking around the setup of our machine. At the Server> System Preferences> Network> I have the modem available as a network item but "modem configured but not connected" appears in the network status list. I doubt this is relevant but just in case that's what I have.
Let's see if we can find what the difference is here and get yours working too so that we have confidence that it is not a fluke for me.