Weird.

I usually save my Icons in TGA or BMP. I'm not sure, but I also don't see the Create Alpha Channel window when I convert them. It appears only when I try to convert pictures or something like that, which originally didn't have the Alpha Channel (mostly JPG files).
About your Icons, so far of all the Icons I've downloaded here, none of
your Icons work. BTN, DISBTN, DISPASBTN, PASBTN: none of them appear in my WE. Maybe it's just me, maybe only my WE doen't show them, seeing I'm the only person who alerts you about a bug of that sort.

Who knows? Sorry about the PMs and posting around, I'll discuss the Bugged Icon topic only in this Icon section, okay?