Join a unit (selected from a listbox) to a group

[Josh79 10]

hi there,

i´m trying to let a unit that has been selected from a listbox in a dialog join to the selector´s group.

so i create a dialog that has been defined in the description.ext by adding an addaction to the player.

by first selecting the unit in the listbox from the dialog and then clicking a button i execute the join script.

dialog:

class listboxA: RscListBox 
{
	idc = 10002;
	x = 0.4;
	y = 0.5;
	w = 0.2;
	h = 0.2;
};
class T_BUTTONJ: RscButton
     {
      idc = -1;
      text = "JOIN";
      x = 0.4 * safezoneW + safezoneX;
      y = 0.7 * safezoneH + safezoneY;
      w = 0.08 * safezoneW;
      h = 0.04 * safezoneH;
             action = "_nil=[]ExecVM ""join.sqf""";
};

join script:

hint "Joined";
lbData [10002, lbCurSel 10002] join (group P1);  
exit

(i´m also trying to get this to work in multiplayer, but i dont know what has to be changed... local variables and global ones...)

thanx for your help

cheers josh