Well, I guess it works out like this. If the illusion is created in the mind of the target, then ultrasound vision is fooled by it (so, basically, if it's a mana spell, rather than a physical one). If the illusion is basically a hologram, something created in a space, but without physical sustance, then the ultrasound vision is not fooled. If the illusion is created in a space, and it has physical substance, then ultrasound vision is fooled. In my humble opinion, judging by the decription of the spell, I would have to say that the physical version does not fool ultrasound vision, but the mana version does. If you want an 'official', if not 'canon', ruling then you could do worse than drop a line to Rob Boyle, whose e-mail address you can find on the
faq page of the official Shadowrun website.