string $material = "lambert2";

global proc transSliderButton( string $HUD )
{
    undoInfo -swf true;

    float $value = `hudSliderButton -q -v $HUD`;

    setAttr ($material + ".transparency") -type double3 $value $value $value ;
}

hudSliderButton -s 5
                -b 5
                -vis 1
                -sl "Trans:"
                -value 0
                -type "float"
                -min -0
                -max 1
                -slw 50
                -vw 50
                -sln 100
                -bl "Close"
                -bw 60
                -bsh "rectangle"
                -brc "headsUpDisplay -remove HUDTransSliderButton"
                -sdc "transSliderButton( \"HUDTransSliderButton\" )"
                HUDTransSliderButton;