Why no Expedia AMS-LHR-SYD VAA availability

I've been looking at AMS-LHR-LAX/JFK options for UCS to the US and expedia offer various VAA fares from AMS that are significantly cheaper than the equivalent VAA LHR-JFK or LHR-LAX fares for example.

However, when I come to look for the same AMS origin fares to Sydney, there doesn't appear to be that option - anyone know why [?]? I'd love to go via AMS (and back!) if it meant a similar reduction as the US fares offered.[}:)]

Thanks.

part *bump* and part *what are you doing to get the NYC fares?*

I can't seem to get anything cheaper on Expedia ex-ams for nyc [:?]

They were showing cheap fares last week. It varies and the cheap fares aren't always there, however they usually are (although things are probably fully booked now in any event).