HUD was an option on JDM vehicles, not many people optioned it though they are quite common in imported U13s in NZ.
Any chance you can try a complete dash cluster in your car? I think that might be the problem. The AU cluster will fit and work perfectly since JDM ones are hard to find. I put a JDM cluster in my AU U13 and just swapped the speedo unit. I'm sure a member on here wouldn't mind trying their AU cluster in your car, such a simple swap.