So. I used that plugin for the previous version of my app but now it stopped working.
I want my app to work in landscape only. Android worked fine, but ios did not.
After hours of tinkering with XDK and plugins (and C2's lock orientation action) the best I managed was that the app started in portrait and then after I changed to landscape locked correctly. It was clearly unacceptable though.
So, I just abandonded XDK and did ios version through phonegap cli + xcode (also installed admob as a plugin). It worked fine and locked correctly.
I just can't recommend XDK for ios builds.