They only fly PX006 SYD-BNE-POM on Monday and Saturday. They fly the BNE-POM segment as PX004 on Wed, Thur, Fri and Sun.
They fly PX054 POM-NRT on Saturdays.
Since they only have the one aircraft operating these routes (their one and only 767-300), I can see no reason that you cannot take PX006 SYD-BNE-POM on a Saturday morning departing at 7:30am and arriving POM at 13:00, then connecting to PX054 departing POM at 14:15 arriving into NRT at 19:55.
See the
PX timetable here.