Change background bluriness when calling Alert or PopupManager

In Flex 4.5 i开发者_高级运维s there please a way to control how blurred is background when displaying an Alert or PopupManager.addPopUp()?

I have playing cards displayed on the background of my game, when displaying a modal popup window with possible bids to the user and can't blur the cards too much (because the player should see them before deciding what to bid).

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This is a clearer statement of the idea provided in the linked post above: http://blog.flexexamples.com/2007/08/14/changing-a-modal-alert-controls-blur-transparency-and-transparency-color/