oops tested more here is the updated stop function in total notice that the condition inside the stopit function has been removed and the condition added around the call for the callback

stop: function(that, e) {
			var o = this.options;
			var self = this;
			if(o.smooth) {
				var os = $(this.element).offset();
				o.beQuietAtEnd = true;
				$(this.helper).animate({ left: os.left - o.po.left, top: os.top - o.po.top }, 500, stopIt);
			} else {
				stopIt();
			}
			function stopIt() {
				$(self.element).css('visibility', 'visible');
				if(that.helper) that.helper.remove();
				if(self.helper != self.element) $(self.helper).remove();
				if(o.ozIndex)
					$(self.helper).css('zIndex', o.ozIndex);
			}
			if($(self.element).prev()[0] != that.firstSibling) {
				$(this.element).triggerHandler("sortstop", [e, that.prepareCallbackObj(this)], o.stop);
			}
			return false;
		}

works in 1.5a (or current SVN).