I've found a way to do it, it kind of strange but it works perfect for me.
First I place my heli with pilot and put a MOVE waypoint close, followed by all the other waypoints.
Then I create a radiotrigger with a bolean in the onactivation field.
eg : choppermove = true
Then I wrote a little script that I execute in the first move waypoint, blackhawk is the name of my chopper.
;keep blackhawk on the ground until the player is onboard.
#loop
~2
blackhawk flyinheight 1
?choppermove: goto "moveon"
blackhawk engineOn true
goto "loop"
#moveon
blackhawk flyinheight 50
exit
Seems that flyinheight 1 keeps him on the ground with engines on even when I put the first waypoint far away from the chopper.. It worked in OFP too, but not that good. The pilot always tried to reach that waypoint at that extreme low height. In arma the chopper stays on the ground and doesn't move at all.
Btw, You can use the same method when you need a chopper extraction that doesn't start from the ground. Just put :
Nameofchopper land "GetIn"
...in the beginning of your script. When you use flyinheight 1, he will land but it's a hard landing, the chopper could be damaged.
Use only MOVE waypoints and always put a second waypoint close after LZ.
Hope this works for you too
Check the 2 attachments below :
example 1 - Chopper is on the ground, engines on, waits until player gets in and moves on.
example 2 - Chopper starts on the ground, engines on, waits for a radio call, flies to LZ and lands, stays on the ground with engines on and waits until player is onboard and moves on.
No getin waypoints involved. I'm glad choppers are a lot easier to handle in Arma then in OFP.