Custom passive buttons...where does DISBTN go?

Ok, let's say I have created a custom passive button, called BTNFishAura. It also has a disabled button, called DISBTNFishAura. Where do I put the DISBTN version, so it will show up instead of a green square? it's the ONLY graphical blurb on my whole map....

ReplaceableTextures\CommandButtonsDisabled\DISBTNName.blp

doh...forgot to add..its technicly PASBTN(blahblahblah), its not a normal button, its one without the border.

Doesn't matter, me thinks. Read above post.