Since you are using CO miles, whether a stopover is permitted solely depends on the redemption rules of CO. It might be more helpful to consult with the program materials or search through the CO forum.

This is the OnePass rules: http://www.continental.com/web/en-US...s/rewards.aspx

"STOPOVER: A stopover is permitted on roundtrip reward travel only. One stopover is permitted, unless otherwise noted. Additional mileage may be required for SaverPass rewards within the Mainland U.S., Alaska and Canada."

In terms of routing, you can do: US to ICN to HKG to US. You might need to fly into a hub served by UA or OZ (ORD, EWR, LAX, SFO) to connect to Asia from PHL. Since HKG and ICN are two different zones by CO rules (ICN is in North Asia while HKG is in South Asia), you need to use miles for an award to South Asia. Although you might spend a lot more days in ICN, you are essentially building an itinerary to HKG with a stopover in ICN.

The hardest part of the itinerary to secure is between HKG and US. There are usually award seats between US and ICN; ICN and HKG. Thus, securing the seats between HKG and US is key (and it might not be non-stop).