WARNING: International award travel novice posting. Drink before replying.

Yesterday, I booked a patience-trying three leg award travel TPE-CAN-PEK-ORD (70k miles in business) since I was a couple of thousand miles short of doing it one-hop. During the award booking with a UA rep, I was able to select my seat on the UA leg PEK-ORD but was informed that my seats on Eva (TPE-CAN) and Air China (CAN-PEK) could not be selected. No biggie. I get it.

Well, this morning, I just happened to jump on Eva's website, and using nothing more than my UA e-ticket number and name, I was able to access my booking and select my seat (looks like I'll be able to choose my meal too closer to travel time). That said, when I attempted to access Air China's US website, the system indicated that neither my e-ticket or UA record locator were found (specifically, it said that the reservation had to have been booked on that site in order to access it there). When I visited Air China's .cn website, well, between my utter worthlessness in Mandarin and their site's pisspoor English translations, I couldn't find any way to access a booking as with Eva.

Any recommendations on selecting my seat on Air China without having to wait til I've rushed through PRC transit immigration in CAN and ran to the gate before pushback?