Put the file littleha.ipl into C:\Program Files\Rockstar Games\Grand Theft Auto Vice City\data\maps\littleha
And the youre ready to go. You may need gravity mod to get to the second island
Heres a link to grav mod:
http://www.thegtaplace.com/downloads/f264-gravmod
Enjoy My Mod And Dont forget to check out my youtube below the mod title =D