Hi, leaving Houston, Texas, USA (8/7/13) to Manila, Philippines (8/9/13), layover for 15 hours at Beijing, China (8/8/13).

Holding Philippine passports, USA Green Cards. We'd like to take a 6 hour tour of Beijing.

Do we go from arrival to customs to immigration and out to BJ or arrival to customs to transit immigration to immigration and out to BJ?

Thank you,