Code:
var button_text = ("HALLOS").split("");
var durchmesser = 100;
var posy = 225;
var posx = 300;
var anfang_winkel = 180;
var oeffnungs_winkel=180;
//
var chars_anz = button_text.length;
var abstand = oeffnungs_winkel/(chars_anz-1);
var rad = Math.PI/180;
//
for (i=0; i<chars_anz; i++) {
var _mc = this.attachMovie("test", "test"+i, i);
_mc.txt.text = button_text[i];
_mc._x = Math.cos(rad*anfang_winkel)*durchmesser+posx;
_mc._y = Math.sin(rad*anfang_winkel)*durchmesser+posy;
anfang_winkel += abstand;
}