jQuery: background-position and Internet Explorer

jQuery (at least up till version 1.2.6) has a problem with Internet Explorer when asking the background-position of an object.
$('h1:first').css('background-position');
In the other A-grade browsers, you get 2 values (in px or %) representing respectively the x-position and y-position of the element. In Internet Explorer (6 and 7) you get undefined. The problem is that IE doesn't know what background-position is, it only knows 2 other calls: background-position-x and background-position-y. Here is a slice of JavaScript code to handle this problem.
(function($) {
  jQuery.fn.backgroundPosition = function() {
    var p = $(this).css('background-position');
    if(typeof(p) === 'undefined') return $(this).css('background-position-x') + ' ' + $(this).css('background-position-y');
    else return p;
  };
})(jQuery);
You can now use this jQuery plugin to get the background-position of an element:
$('h1:first').backgroundPosition();
There is a ticket open in the jQuery Bugtracker about this isue, but it is weird that such a simple problem isn't fixed already.