How to change color around Alert component

[miguelp]

hi, i'm having a hard time trying to change the background color around a alert component.
What i wanna do is when i fire up an alert window, the background around it, be black with _alpha at 50%, so if i have some objects on the stage i can see them but darker.

here is the code i have so far:

import mx.controls.Alert;
_global.styles.Alert.setStyle("themeColor", "haloBlue");
_global.styles.Alert.setStyle("color", 0x000099);
_global.styles.Alert.setStyle("disabledColor", 0x848384);

// Define action after alert confirmation.
var clickHandler:Function = function (evt_obj:Object) {
if (evt_obj.detail == Alert.OK) {
trace("OK clicked now do something");
}
};

// Show alert dialog box.
Alert.show("Alert: error \n you have to login, in order to view this resource.", "Alert", Alert.OK, this, clickHandler, "Icon", Alert.OK);



how can i change the color around the component?