Cathay Pacific Asia Miles - trying to redeem miles for US flights

I'd like to unload some of my AsiaMiles on a flight here in the US. The strange thing is that when I do flight searches from Denver on the AsiaMiles site and attempt to pick a carrier, I get Air China as my only option. My assumption is that Air China is allowing redemption of miles on United codeshare flights. However, when I try to fill in the actual redemption form, it asks for the flight number or flight time. I'm not sure what to put there since Air China does not actually operate flights that start and end within the US.

Can anyone enlighten me how I can go about this? Also, does anyone know how far out I should try to book AsiaMiles redemptions for non Cathay Pacific flights in the US? Is there any way to do last minute bookings? Thanks.

You may of course also book with Japan Airlines as they are members of Asiamiles.

The asiamiles website unfortunately is not that great (or accurate). If you're looking for US flights, be prepared to plan way in advance or on very short notice.

Best for you to call Asiamiles to do any sort of booking.

Thanks. Sounds like calling them is going to be the best option.