[jQuery] combining slideup, post, slidedown

[Althalos]

Hi. I am trying to make a div slide up, update through $.post and then
slide down again. I have the following code:
  $("a").click (function() {
          $("#content").slideUp('slow', function () {
          $.post('http://uf.ekdahlproduction.com/itsvintage/text.php',
{site: $(this).attr('rel')}, function(data) {
          $("#content").html(data);
          $("#content").slideDown('slow');
          });
});
});

However, the div just goes up and down without any content on it. Can
anyone help me sort this out?

(I know the post thingy is working, because it works if I write the
$.post and its callback outside the callback function of slideUp.
Then, however, it will be possible to see the new content when it's
still on its way up)

thank you