In the fairly recent past, a Fuller joystick emulation was added to fuse, and it worked. However, some time between then and revision 4259, it appears that it no longer works. I have tried to test it with The Pyramid and Alchemist, and apart from some random left, right and fire, it seems to do nothing - certainly, it doesn't respond to the stick.
This is not a huge problem as I don't know of any program that supports Fuller but not also either Kempston or Cursor. However, it would be nice to have it working.
Works for me.
$ ./fuse -fuller Pyramid.tzx
When Fuse starts, select a joystick (I did Options / Joysticks / Keyboard and then selected Fuller from the radio buttons on the left as I don't have a real joystick).
In-game, press 1 to select Fuller.
QAOPspace now work as up-down-left-right-fire for me.
Ah, that's sorted it - I'd forgotten there was another option to enable.