[Moo] is there such thing as a 'onTween' event

[4fingers]

Hi

Sorry if this has been asked already but I couldn't find any refrence
to it in the documnets, but is there an onTween event i.e.

var tween = new Fx.Tween(element, {
    link: 'chain',
    duration: 'long',
    transition: 'linear',
    onTween: function(){
        iFrameShim.position();
    },
    onStart: function() {
        iFrameShim.show();
    }
});

Thanks