Icons for Applications

I've been working on creating an rpm for btbuilder for fedora 17. I followed various information I found to setup a desktop file and icons. The desktop file works. I see btbuilder in the list of applications I can run but it is using a generic icon. I installed the files:

/usr/share/icons/hicolor/16x16/btbuilder.png
/usr/share/icons/hicolor/32x32/btbuilder.png
/usr/share/icons/hicolor/48x48/btbuilder.png

I added a post step to do:

/bin/touch --no-create %{_datadir}/icons/hicolor &>/dev/null || :

Is there something else I need to do? I was looking at some other rpms. gnome-games put the icons like I did. Others seem to put images in /usr/share/pixmaps/. Which should I be doing?