svg 2 gif/png

I'm moving all of my dynamic image generation to svg.
Not only does it look better, but it is less resource intensive on my 
server allowing me to generate the svg on demand instead of 
pre-generating (via cron) twice a month like I had to do with gd dynamic 
generation.

However, some browsers *cough*IE*cough* do not support SVG, so I still 
need png or gif fallback (I'll decide which after investigating size 
difference).

Example SVG to convert -

http://www.shastaherps.org/map/map22.svg

Using convert from ImageMagick in the CLI is fast enough that I may just 
use the ImageMagick php module and do the fallback dynamic for the IE 
users, but I've run into a bit of a snag - it seems that ImageMagick 
doesn't understand xlink.

IE running

convert --size=800x574 map22.svg map22.png

on above file results in a nice pretty map with the county and text, but 
the colored hexagons are not displayed.

Is there an easy way around this? IE a php class/function that 
understands SVG w/ xlink and can replace the use tags with the polygons 
they refer to? If not, I'll have to try to write one, but I'd rather not ...

Thanks for suggestions. It is too bad ImageMagick doesn't understand the 
use tag and xlink, that is one of the more useful features of SVG that I 
have personally found, makes dynamic generation so much easier.