webview orientation issue on animation (iPad)

i have a webview inside a window that gets animated (only a simple slide down) on clicking the header of the webview. which works great, however...

the webview thinks its orientation is being changed. i presume this is a CSS3 problem in the webview because i am using the new @media queries features of CSS3.

@media only screen and (orientation:landscape){
}
@media only screen and (orientation:portrait){
}

these work fine to style the html page in my webview and detect a normal orientation change in the ipad simulator. they only get confused when the webview is animated (either individually or when its wrapping window is animated.)

this is a fairly bizarre bug, and i'd be surprised if anyone else has come across it, but any help or suggestions would be greatly appreciated!

thanks Sam