Tab focus on QToolBar QToolButtons

[bmn]

I'm developing some software with a GUI that must be controllable with only 4 buttons. I plan on mapping the buttons to TAB, SHIFT-TAB, ENTER and ESC. The TAB/SHIFT-TAB conveniently allows me to tab through fields and buttons.

Unfortunately, I can't work out a way to be able to tab through a QToolbar's QToolButtons. Setting the focus policy of the toolbar and its individual buttons doesn't seem to work. Does anyone know of a solution that will allow me to tab through the tool buttons in a toolbar?

[bmn]

Does no one have any ideas?