Form select gadgets

Is there any way of adding a down arrow to the form select gadgets,
maybe using CSS? The select gadgets here look a bit odd if I change
the frame to be raised (because they look like normal buttons), but I
think raised with a down arrow (or rather, a V with a line under it)
at one end, or even Windows-stye (embossed but with a raised down
arrow button at one end) would (a) fit in with the OS4 style better
and (b) be more intuitive for the user, as it's not obvious it's a
popup until the mouse is hovering over it. Actually I thought RISC OS
normally had a popup button next to this sort of thing, so something
similar might make sense there too?

Can it be done in the default style CSS, or does it need to be coded
into the select forms in the main code?

Chris