Launching YouTube from UIWebView, it's always in landscape

I'm launching YouTube from an embed in a UIWebView as per this example from the YouTube API blog, with HTML something like:

<object width='320' height='260'>
    <param name='movie' value='http://www.youtube.com/v/{0}&f=gdata_videos'></param>
    <param name='wmode' value='transparent'></param>
    <embed src='开发者_开发技巧http://www.youtube.com/v/{0}&f=gdata_videos' type='application/x-shockwave-flash' wmode='transparent' width='320' height='260'></embed>
</object>

When I click the thumbnail and "play" button in the UIWebView, the YouTube app launches in landscape mode. The UIWebView itself is in portrait orientation, as is most of the app, so this is kind of obnoxious, especially if the particular video is also shot in portrait.

Is there any way to control the orientation of the launched YouTube app? I tried swapping the width and height in the HTML, but while that affects the thumbnail, it doesn't affect the YouTube app.