I am just pulling out this thread.

Booked a Ticket in Y-cl MEX-UA-SFO <stopover> SFO-UA-HNL.

Was able to upgrade my ticket with Mileage Plus miles. But I was charged two separate upgrade awards, due to the stopover (as I was told):
- Feb. 16, 2011 OW UPGRADE N AMERICA-HAWAII FROM ECONOMY (7,500)
- Feb. 16, 2011 OW UPGRADE N AMERICA-CARIBBEAN FROM ECON (7,500)

The only rules about upgrades I found were the following:

United Upgrade Award rules - effective July 1, 2009, saying:

• If fare rule permits stopovers, a maximum of 2 stopovers are allowed per award. Awards are one way.
• When United award travel originates in Asia, Australia, New Zealand, Europe or Latin America and entails routing via the U.S., two awards are required: one to/from the U.S., and another between the U.S. and your final destination.

Anybody knows, if on my routing a stopover on the award upgrade is allowed?
Mexico - Hawaii.
Hawaii is a state of the U.S. or?