Bitmap button help

I could use a hand from a button wiz...

I want to use a generic button for most of my needs, overlaying either text or another bitmap on top of it, as opposed to creating seperate button bitmaps with the text/graphic in the image.

Visually, this is working fine. However, the top layer is catching the mouse, not allowing the underlying button to be depressed unless you hit that small area the overlay isnt occupying.

What I wish to do, is have the overlay ignore the mouse completely, allowing the underlaying button to recieve any activity.

My example usage follows:

new GuiBitmapButtonCtrl() {
               profile = "LobbyGuiButtonProfile";
               horizSizing = "relative";
               vertSizing = "relative";
               position = "8 284";
               extent = "47 32";
               minExtent = "8 8";
               visible = "1";
               command = "ChooseModelDlg.PreviousModel();";
               text = "Button";
               groupNum = "-1";
               buttonType = "PushButton";
               bitmap = "~/data/ui/character/button0";
               Enable = "1";
           new GuiBitmapCtrl() {
               profile = "GuiDefaultProfile";
               horizSizing = "center";
               vertSizing = "center";
               position = "16 288";
               extent = "30 26";
               minExtent = "8 8";
               visible = "1";
               bitmap = "~/data/ui/character/Larrow";
               wrap = "0";
            };
            };