Check out this method, it allows for an optional "hole" parameter. This is found in the ProgrammaticSkin class of the flex framework.
http://opensource.adobe.com/svn/opensource/flex/sdk/trunk/frameworks/projects/framework/src/mx/skins/ProgrammaticSkin.as
/**
* Programatically draws a rectangle into this skin's Graphics object.
*
* <p>The rectangle can have rounded corners.
* Its edges are stroked with the current line style
* of the Graphics object.
* It can have a solid color fill, a gradient fill, or no fill.
* A solid fill can have an alpha transparency.
* A gradient fill can be linear or radial. You can specify
* up to 15 colors and alpha values at specified points along
* the gradient, and you can specify a rotation angle
* or transformation matrix for the gradient.
* Finally, the rectangle can have a rounded rectangular hole
* carved out of it.</p>
*
* <p>This versatile rectangle-drawing routine is used by many skins.
* It calls the <code>drawRect()</code> or
* <code>drawRoundRect()</code>
* methods (in the flash.display.Graphics class) to draw into this
* skin's Graphics object.</p>
*
* @param x Horizontal position of upper-left corner
* of rectangle within this skin.
*
* @param y Vertical position of upper-left corner
* of rectangle within this skin.
*
* @param width Width of rectangle, in pixels.
*
* @param height Height of rectangle, in pixels.
*
* @param cornerRadius Corner radius/radii of rectangle.
* Can be <code>null</code>, a Number, or an Object.
* If it is <code>null</code>, it specifies that the corners should be square
* rather than rounded.
* If it is a Number, it specifies the same radius, in pixels,
* for all four corners.
* If it is an Object, it should have properties named
* <code>tl</code>, <code>tr</code>, <code>bl</code>, and
* <code>br</code>, whose values are Numbers specifying
* the radius, in pixels, for the top left, top right,
* bottom left, and bottom right corners.
* For example, you can pass a plain Object such as
* <code>{ tl: 5, tr: 5, bl: 0, br: 0 }</code>.
* The default value is null (square corners).
*
* @param color The RGB color(s) for the fill.
* Can be <code>null</code>, a uint, or an Array.
* If it is <code>null</code>, the rectangle not filled.
* If it is a uint, it specifies an RGB fill color.
* For example, pass <code>0xFF0000</code> to fill with red.
* If it is an Array, it should contain uints
* specifying the gradient colors.
* For example, pass <code>[ 0xFF0000, 0xFFFF00, 0x0000FF ]</code>
* to fill with a red-to-yellow-to-blue gradient.
* You can specify up to 15 colors in the gradient.
* The default value is null (no fill).
*
* @param alpha Alpha value(s) for the fill.
* Can be null, a Number, or an Array.
* This argument is ignored if <code>color</code> is null.
* If <code>color</code> is a uint specifying an RGB fill color,
* then <code>alpha</code> should be a Number specifying
* the transparency of the fill, where 0.0 is completely transparent
* and 1.0 is completely opaque.
* You can also pass null instead of 1.0 in this case
* to specify complete opaqueness.
* If <code>color</code> is an Array specifying gradient colors,
* then <code>alpha</code> should be an Array of Numbers, of the
* same length, that specifies the corresponding alpha values
* for the gradient.
* In this case, the default value is <code>null</code> (completely opaque).
*
* @param gradientMatrix Matrix object used for the gradient fill.
* The utility methods <code>horizontalGradientMatrix()</code>,
* <code>verticalGradientMatrix()</code>, and
* <code>rotatedGradientMatrix()</code> can be used to create the value for
* this parameter.
*
* @param gradientType Type of gradient fill. The possible values are
* <code>GradientType.LINEAR</code> or <code>GradientType.RADIAL</code>.
* (The GradientType class is in the package flash.display.)
*
* @param gradientRatios (optional default [0,255])
* Specifies the distribution of colors. The number of entries must match
* the number of colors defined in the <code>color</code> parameter.
* Each value defines the percentage of the width where the color is
* sampled at 100%. The value 0 represents the left-hand position in
* the gradient box, and 255 represents the right-hand position in the
* gradient box.
*
* @param hole (optional) A rounded rectangular hole
* that should be carved out of the middle
* of the otherwise solid rounded rectangle
* { x: #, y: #, w: #, h: #, r: # or { br: #, bl: #, tl: #, tr: # } }
*
* @see flash.display.Graphics#beginGradientFill()
*
* @langversion 3.0
* @playerversion Flash 9
* @playerversion AIR 1.1
* @productversion Flex 3
*/
protected function drawRoundRect(
x:Number, y:Number, width:Number, height:Number,
cornerRadius:Object = null,
color:Object = null,
alpha:Object = null,
gradientMatrix:Matrix = null,
gradientType:String = "linear",
gradientRatios:Array /* of Number */ = null,
hole:Object = null):void
{
var g:Graphics = graphics;
// Quick exit if weight or height is zero.
// This happens when scaling a component to a very small value,
// which then gets rounded to 0.
if (width == 0 || height == 0)
return;
// If color is an object then allow for complex fills.
if (color !== null)
{
if (color is uint)
{
g.beginFill(uint(color), Number(alpha));
}
else if (color is Array)
{
var alphas:Array = alpha is Array ?
alpha as Array :
[ alpha, alpha ];
if (!gradientRatios)
gradientRatios = [ 0, 0xFF ];
g.beginGradientFill(gradientType,
color as Array, alphas,
gradientRatios, gradientMatrix);
}
}
var ellipseSize:Number;
// Stroke the rectangle.
if (!cornerRadius)
{
g.drawRect(x, y, width, height);
}
else if (cornerRadius is Number)
{
ellipseSize = Number(cornerRadius) * 2;
g.drawRoundRect(x, y, width, height,
ellipseSize, ellipseSize);
}
else
{
GraphicsUtil.drawRoundRectComplex(g,
x, y, width, height,
cornerRadius.tl, cornerRadius.tr,
cornerRadius.bl, cornerRadius.br);
}
// Carve a rectangular hole out of the middle of the rounded rect.
if (hole)
{
var holeR:Object = hole.r;
if (holeR is Number)
{
ellipseSize = Number(holeR) * 2;
g.drawRoundRect(hole.x, hole.y, hole.w, hole.h,
ellipseSize, ellipseSize);
}
else
{
GraphicsUtil.drawRoundRectComplex(g,
hole.x, hole.y, hole.w, hole.h,
holeR.tl, holeR.tr, holeR.bl, holeR.br);
}
}
if (color !== null)
g.endFill();
}
}