Well, after several tests, I finally opened the EXE using PE Explorer. Then, I was able to modify some resources with the bitmaps I like, but the result was a mess in the background color of all the HFS's interface icons (nevermind if replacing tray icons succeded) and the tray icons turned to transparent, I mean no icon, just an empty space in the tray. The two icons I'm trying to replace are the default HFS tray icons.
Help?