How to send faxes directly from within LibreOffice?

Up to version 4.3, one could use the spadmin tool to setup a fax driver – which worked perfectly for me in OpenOffice and later LibreOffice. Having updated to version 5.x, that fax driver stopped working – and the spadmin tool had disappeared from LibreOffice.¹ Simply copying the psprint.conf file to the new location didn't help (as the linked post¹ indicates).

As a work-around I currently have to print my faxes and then scan them to the fax printer – which obviously defeats the purpose of a "paperless office".

Is there any (not too difficult) way to restore the direct "print-to-fax" functionality in LibreOffice?

PS: I have a Brother MFC 9120 CN here, the corresponding drivers (LPD, CUPS, FAX) are installed on my Ubuntu 12.04 machine. And before you ask: No discussion please about upgrading to 14.04/16.04, that's not part of this question :)

^{1: see e.g. spadmin gone from libreoffice}

On further investigation, several hints led me to a proposed solution¹: Brother provides a fax modem driver (brfaxmodem-1.1.3-1.i386.deb) which you can download from their support site (link is for MFC9120CN). Their instructions then say:

1. have your printer connected via USB
2. install the driver: sudo dpkg -i brfaxmodem-1.1.3-1.i386.deb²
3. install the efax package: sudo apt-get install efax
4. open /etc/efax.rc using a text editor and change "DEV=ttyS1" into "DEV=modem"

Now you should be able adding a new printer: "AppSocket/HP JetDirect" with Hostname: localhost, Port: 9900, printer typ: Generic -> Raw Queue. Having that done, check that /etc/cups/printers.conf contains socket://localhost:9900. efax doesn't start automatically, so you'll have to do that manually when you need it (or create yourself a startup script to have Ubuntu taking care for that at boot).

If LibreOffice/OpenOffice doesn't detect this "fax printer" (which according to the change logs it should), Fax4CUPS might be needed:

… So the current LibreOffice version in Ubuntu 14.04 LTS is obsolete. I've updated my LO to 5.0.1.2 and the fax integration has changed. spadmin no longer exists, and an external script, fax4CUPS is required.

Fax4CUPS is a CUPS backend for efax/hylafax/mgetty-fax. At the URL given you can find a .deb package you again need to install via sudo dpkg -i fax4cups_2.0-1_all.deb. Further instructions then can be found in its man page: man fax4CUPS.

¹_{not yet tested by me due to lack of time – but I don't want to a) lose the notes and b) keep them away from you. I will accept this answer once I've tested it successfully.}
²_{on a 64bit installation, you'll obviously need the 32bit support for that, unfortunately}