[jQuery] using animate() with duration/queue object and callback doesn't work

[chrismarx]

hi,
 this works fine

$elem.animate( {opacity:0}, 600, callback)
          .animate( {height:"hide"}, 700);

but this doesn't

$elem.animate( {opacity:0}, {queue:false, duration:600}, callback)
          .animate( {height:"hide"}, 700);

nor this

$elem.animate( {opacity:0}, {queue:false, duration:600,
callback:callback})
          .animate( {height:"hide"}, 700);


what am i missing?