You could always add the Rabaul map as an additional mod map within HSFX6.
A new version of Rabaul including Green Island is in progress at SAS -- but not yet released.
The old beta map can still be downloaded here
http://www.mediafire.com/?2betfxw71jaxk3p
In HSFX6 copy root\Files\maps\all.ini
to root\MODS\MapMods\maps
Then edit root\MODS\MapMods\maps\all.ini
add the text
Setouchi_beta Setouchi_beta/load.ini
Rabaul_beta Rabaul_beta/load.ini
RabaulOnline Rabaul_beta/net_load.ini
The map and _Tex folders also go into root\MODS\MapMods\maps
The maps should now appear in your FMB menus
I think that all the objects required are already in HSFX6.