在扩展asp.net Web控件时，应该在哪个事件中注入其他Web控件？

I'm trying to avoid a composite control or using and ASCX by extending an existing control. However, I'm having trouble with getting the controls added to the inherited control and keep their view-state/post-back integrity. Whenever I add the controls during pre-render, the controls show up, but the post-back throws a viewstate exception. I tried adding them both there and during LoadViewState (which of course was a long-shot silly). Init is not available from the control which I'm extending.I'm trying to avoid a composite control or usin