[Plugin: ThickBox] Closing a Modal Window?

I’ve got a question and I can’t find the answer anywhere on the interwebs. Thickbox is working great for my popups. I’m using modal =true because I want to create my own close button. I also want to be able to close the modal window by click on the overlay (the gray background div). The close button works fine, but I can’t get the overlay to accept any clicks. Here’s my code:

$(".closebiopopup, #TB_overlay").bind("click", function(e) {
tb_remove();
return false;
});

Any ideas about how to bind an event to the overlay?