How does libreoffice get available paper sizes?

FreeBSD 10.0 RELEASE with Xfce4, CUPS printing, LibreOffice, build ID FreeBSD ports 4.2.5_4

Firefox and Gnucash can see all the paper sizes defined in the PPD file for my Samsung ML-2850 B&W laser. But all LO components only offer me a subset. Switching LO between PDF printing and PostScript printing does not change the list.