Customizing the keyboard with unusual keys

I am using LO 4.2.8.2 with Ubuntu 14.04. And I have a Sun keyboard.

LO provides a nice Customize feature, which gives you a list of keys, shows what commands they are currently linked to, and allows you to link them to all sorts of weird and wonderful things. You can even save the settings, and modify the saved setting offline.

So I have bound Undo and Redo and even Find (though I cannot bind it to whatever ctrl-F is bound to).

But what about the keys that are not listed (notably Copy, Paste and Cut)? They are all picked up by the OS, and xev shows that they have keysyms linked to them (XF86COPY, etc). But even if I attempt to set them offline on the saved .cfg, using every plausible naming, they are ignored (without even an error message).

Oddly enough, the official list does include SunProps and SunFront (whyever those two?) and I can bind SunProps to the Copy function.

But that at least means that the string “SunProps” is stored somewhere within the system, so I went looking for it using strings and egrep on every binary and every library that seemed to have the remotest connection with LO, and I looked also in every plausible share directory. But to avail (yet it must be there somewhere, so where is it?)

I have googled, and found that this problem has been reported several times, but noone has offered an answer.

So please, how can I work around this problem? I don’t really want to go to the trouble of downloading the LO sourcecode and excavating it that way.