Can't get layouts switched by rotation in iOS Simulator

Can't get layouts switched by rotation in iOS Simulator

Hello, I'm making my first try in developing an iPad App with JQuery Mobile 1.0a4.1 and Phonegap. It all goes fine so far, but I can't get my layouts "switched" on rotation in iOS Simulator.

If I try my page with different window widths / heights simply in Chrome on desktop - it's all fine, "body" is getting classes "landscape" or "portrait" and styles are changing accordingly to them, as I wrote in theme. But in iOS Simulator (compiled) - this trick doesn't work anymore... May be there are some settings I'm not aware of?

Thanks, if someone can help :)

Greetings,
JB