I've got Vista installed on a PC with a US keyboard layout and Japanese input (IME) installed.
On my work PC running XP I've got the same setup.
In XP, I can input in Japanese using the US keyboard layout.
In Vista, when Japanese input (IME) is on, it changes the keyboard layout to the default Japanese keyboard layout.
I've looked at both Vista and XP's settings for 'Text Services and Input Languages' and can see no difference, or where it could be changed.
How can I setup my Vista PC to use Japanese input (IME) using the US keyboard layout?