PS/RAW format detection only works with Samba?

[Christoph]

I'm using KDE to print to my PCL printer connected to a remote CUPS server. When I set up kprinter to use the generic Postscript driver, Postscript is generated on my machine and sent to my CUPS server. Sending it over Samba works fine, the CUPS server detects the Postscript format, processes it using the PPD file and prints it out perfectly. But if I connect to it using Remote LPD or Remote CUPS in kprinter, CUPS always detects the incoming PS file to be RAW. On the CUPS server itself printing a .ps file using lpr works fine.

Why is CUPS unable to detect the format of a print job coming in via Remote LPD or IPP, but can do it via Samba and Local LPD?

Thanks,

Christoph