If you only need the standard functionality of hide only with visibility:hidden to keep the current layout you can use the callback function of hide to alter the css in the tag. Hide docs in jquery
An example :
$('#subs_selection_box').fadeOut('slow', function() {
$(this).css({"visibility":"hidden"});
$(this).css({"display":"block"});
});
This will use the normal cool animation to hide the div, but after the animation finish you set the visibility to hidden and display to block.
An example : http://jsfiddle.net/bTkKG/1/
I know you didnt want the $("#aa").css() solution, but you did not specify if it was because using only the css() method you lose the animation.