Install /usr/ports/print/hplip-plugin (in the past mirror for that one was quite unstable so it was difficult to download all files needed). After that install /usr/ports/print/cups-filters as well (have no clue why they are removed from normal cups installation but without them you might have lot of errors similar to "Returning IPP client-error-document-format-not-supported for Print-Job". Printer should be working after this.
