http://www.reddit.com/r/arma/comments/19sjsc/how_to_import_most_of_the_arma_ii_stuff_to_the/Step 1: Make a new folder in your Arma 3 directory (C:\Program Files (x86)\Steam\steamapps\common\Arma 3) call it "@Arma" or something does not really matter.
Step 2: Now go to your Arma 2 directory (normaly C:\Program Files (x86)\Steam\steamapps\common\Arma 2) and copy the AddOns folder there to your recently created folder in the arma 3 directory (the @Arma folder you just created).
Step 3: Since Arma III is not Arma II you will need to delete some files of what you copied over. You will need to delete the following files:
editor.pbo
editor.pbo.bi.bisign
editor.pbo.bi2.bisign
ui.pbo
ui.pbo.bi.bisign
ui.pbo.bi2.bisign
UIFonts.pbo
UIFonts.pbo.bi.bisign
uifonts.pbo.bi2.bisign
modules.pbo
modules.pbo.bi.bisign
modules.pbo.bi2.bisign
anims.pbo
anims.pbo.bi.bisign
anims.pbo.bi2.bisign
if you leave any of these files in you will get a black screen at the intro. (If you dont delete anims the walking animation will be fucked up)
Step 4: Now in steam right click Arma 3 Alpha > Properties > Set Launch Options... and put "-mod=@Arma" in that text field that pop up and press OK
Step 5: Start the damn thing. It will take a significantly longer time to get to the main menu since its so much to load. Now when your at the main menu go to editor and there your go.
Notes:
Spawning in characters from arma 2 will crash the game. (most likely because of new clothing system and such)
Most of the reload animations of the arma 2 weaps does not work in most stances.
Scuba Diving does work in charnarus and utes but the under water terrain is not that pretty...
You will get a metric shit load of errors and such playing this... that is quite hard to avoid without reprogramming arma II so DEAL WITH IT!
Do not spawn vehicles from the Blufor or Opfor or Indiependent/Civilan menu USE EMPTY since if you not it will spawn AI inside the vehicles and crash your game
