Multiline text for radiobutton

I have dynamic radiobuttons with external text. The radio buttons have multiline text.
But on rollover of the radiobutton, the text width reduces.
How to make it fix? Also it does not display correct height of the field.

Here is the code

import fl.controls.RadioButton;
import fl.controls.RadioButtonGroup;
import fl.controls.ButtonLabelPlacement;

var str:String = "test multiline text test multiline text test multiline text test multiline text test multiline text";
//var str:String = "test multi";

var rbg1:RadioButtonGroup = new RadioButtonGroup("group1");

var rb1:RadioButton = new RadioButton();
rb1.textField.condenseWhite = true;
rb1.textField.multiline = true;
rb1.textField.wordWrap = true;
rb1.textField.autoSize = TextFieldAutoSize.LEFT;

var rbf:TextFormat = new TextFormat();
rbf.align = "left";
rbf.color = 0x333333;
rbf.font = "Verdana";
rbf.size = 15;
//rb1.labelPlacement = "LEFT";
rb1.width = 500
rb1.textField.width = 400;
rb1.label = str;

rb1.setStyle("textFormat", rbf); = rbg1;
rb1.move(100, 100);
rb1.addEventListener(MouseEvent.CLICK, announceCurrentGroup);

var rb2:RadioButton = new RadioButton();
rb2.label = "Choice B"; = rbg1;
rb2.move(100, rb1.x+rb1.textField.height+10);
rb2.addEventListener(MouseEvent.CLICK, announceCurrentGroup);

function announceCurrentGroup(e:MouseEvent):void {
    var group:RadioButtonGroup = RadioButtonGroup.getGroup("group1");
    trace("The currently selected radio button is: " + group.selection.label);

Any help??
Thanks in advance!