Issue applying DD_belatedPNG png fix on images within a lightbox (IE6)

I am trying to invoke the DD_belatedPNG fix on images within a lightbox once it has been called. Okay, so that's easy enough with colorbox:

$(el).colorbox({
  ...
  onComplete:function(){
    DD_belatedPNG.fix('#product_pop .fixme');
  }
});

This works fine, and the pngfix is applied BUT it only works the first time the li开发者_StackOverflow中文版ghtbox is called, all subsequent calls to the lightbox don't seem to have the PNG fix applied :S

I've also tried calling the pngfix only for that first time that the lightbox is opened, and each subsequent view, do nothing (as per the example below) - but that doesn't seem to help either.

Example here