I had to shut down X, by using ctrl+alt+bkspace
or let the movie play it's course.
I think I found another key combo, but locked my Z once trying this and had to reset the switch in the battery compartment
BTW, I have a lot of really bad, zaurus incompatible movies...
EDIT: (again)
There are 2 logs you can save under the options menu.
You have to move the dialog to the bottom to access the save button.
The smplayer log shows some keyboard shortcuts, but some are only windows keyboard shortcuts.
BTW, these logs are deleted once you exit smplayer.
EDIT2:
The stop shortcut is mapped to a "media stop" key according to the log
pause is mapped to "space"