Okay, I'm really feaking confused. I managed to change the flashing orange button on my virtual machine (it was IMAGE 1151 for me) but using the very same .msstyle on my main install, it apparently doesn't use the same graphic resource. What determines which resource is used? The resolution you are using in Windows, or something along those lines? It's super weird.
EDIT: Wow, when I shut down Ultramon the highlight works as intended. What the hell is Ultramon doing to affect the theme