Q: Can I backtrack?
A: You can backtrack within countries and continents, but you cannot re-enter a continent after leaving it, except: (a) a transit without stopover in Asia on a flight between Europe and SWP or vice versa, (b) a transit without stopover in Asia on a flight between North America and SWP or vice versa, (c) a transit without stopover in North America on a flight between South America and SWP, Asia or Europe or vice versa, (d) a transit without stopover in Europe on a flight between Europe and Ghana or Nigeria or vice versa. Any of these transit without stopover benefits can be taken in either direction (eg. Europe-SWP or SWP-Europe) and either before or after you wish to enter the continent for the second time to use your stopovers there. You can only leave and re-enter the continent of origin once, except for North America where you may have an additional transit without stopover.

Only one intercontinental departure and one intercontinental arrival permitted in each continent.
Exceptions: Two permitted in North America. when one is a transfer without stopover.
Two permitted in Asia when one is a transfer without stopover or on direct single plane service between the Southwest Pacific
And Europe.

Ok, Can someone help me with this. I'm confused.

I'm trying to book DONE4 Originating from BKK
MY first leg is BKK-SYD
My second leg is SYD-LHR with transit in either bkk, hkg or sin.
I called the AA RTW desk and they said that I was unable to do this.
Can someone confirm???

Much appreciated.