Before trying to hack it, why not trying to contact Barna?
Maybe he can just make that "Nothing thing" a custom image...
If his mail address is not public, the forum admin (Ian?) may privately ask him about it.
I tried going on the web address reported in the plugin, but the last post on the forum was in 2006.
Oh, as far as plain easy moddable resources go, the plugin seems to be not packed, and no image is avail to be changed. So yes, we need something better than a resource hacker
But first we should try to contact him, it's not long he was here after all, just late 2009!