Auto-resizing problem in scrollview subviews

I have a scrollview on a UIView and a series of UIImageViews are placed on the scrollview in a serial man开发者_高级运维ner. My problem is that the image views are not resizing when the device is rotated. In the viewWillAppear, I added

imageView.autoresizingMask=UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth;
    FirstScrollView.autoresizingMask=UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth;

Can anybody help me?

You can set it with Interface builder.