Originally Posted by
Himeno
You can't buy extra segments using the online tool.
Correct
And then if one tries to purchase the ticket by other means - say through the AA RTW desk - one gets in to the rule regarding the fare being the higher of country of origin and country of purchase
Since the OP will be in Europe for some time before setting off on the ex-FRA RTW, then s/he will be OK- but if wanting to puchase in Australia before departure then there will likely be a problem