如何将自定义回调函数附加到jquery自动完成扩展?

I'm using the jquery autocomplete 1.0.2 extension by Dylan Verheul, Dan G. Switzer, Anjesh Tuladhar, Jörn Zaefferer. I am attempting to execute my own callback function when .show() and .hide() are called from within the autocomplete control. I haven't found any way for it to actually recognize my callback function. If anyone is familiar with this control and can help I would be greatly appreciative.I'm using the jquery autocomplete 1.0.2 extensi