12.04 - Why can't I set the correct icon for my launcher?

I created a launcher for Eclipse (STS, actually). When I double-click it, it starts up Eclipse. What's annoying is that the icon is the gnome footprint with the left-pointing arrow. I'd like to set it to use the icon that came with STS.

I edited ~/Desktop/Eclipse.desktop and commented out the Icon line and replaced it with this (where "" is the path to my homedir):

Icon[en_CA]=/apps/springsource/sts-2.9.1.RELEASE/icon.xpm

I restarted the box, but the icon didn't change. I verified that the path I entered is the path to the xpm file.