Just checked it out, VirtualBox (Linux i386) can not boot amithlon. The boing-ball starts jumping - kernel is booting - but the Amiga never shows up.
Maybe to much hardware dependings for a virtual system. In this case an emulated emulation is not the best way to work in.
(Win)UAE should do this job a lot better. Its also possible to export the installed amithlon OS3.9 (hardfile) and let UAE access it.