Mine runs through the wire tray.
First pic shows during front end disassembly, vacuum hose is lying on top of the wire tray (it simply had slipped out of place).
Second plc shows during reassembly.
Although I agree, it is not totally clear in the AIM, to me it looked like the vacuum hose ran through the wire tray. Also, this would be a more logical choice than simply lying acrossl the back of the engine.