According to a thread I just read at stackOverflow (http://stackoverflow.com/questions/6088409/svg-drop-shadow-using-css3
]) You can't do this with a box-shadow.
Looks like the (unavoidable) way to go is (a) filters or (b) non-vector images for those misbehaving browsers.
I'm still covering the whole svg and css idea, though from the little I've looked at, I'm yet to recal a css property that works for both html and svg. Take for instance the padding and margin attributes. Fine for html, no effect (chrome 19) for svg. Or take fill and stroke. Fine for svg, no effect in html.
No doubt(?), there are some properties that work for both. So far I'm tending towards the view that the syntax and use is similar for html and svg css, while the remainder of the ins and outs aren't.