beamer "second screen" with XeLaTeX

Question

I want to use beamer to project slides onto one screen and my notes onto a second screen. Beamer's show notes on second screen option is designed for this purpose. It requires the pgfpages package, and it is supposed to create PDF pages of ordinary height but twice the ordinary width, so that half of the page can be projected onto one screen, half onto the other.

The option works as intended when I use pdflatex. But when I use xelatex (from MikTeX 2.9), I get pages of only the normal width. The pages are my normal slides; my "note" slides are not created. Here is an example:

\documentclass{beamer}
\usepackage{pgfpages}
\setbeameroption{show notes on second screen=right}
\begin{document}
\begin{frame}{Note test}
  \begin{itemize}
     \item<1-> Eggs
     \item<2-> Plants
       \note[item]<2>{Tell joke about plants.}
  \end{itemize}
\end{frame}
\end{document} 

When I use pdflatex, this code produces a PDF file of double width, with note slides on the right. When I use xelatex, it produces a PDF file of normal width, and no note slides are included. Changing the first line to \documentclass[xelatex]{beamer} makes no difference.

Is there anything that I can do to make the show notes on second screen option work with xelatex?

I am using beamer 3.27 and pgfpages 0.02 (which is distributed with v3.0 of the pgf package).

Answer 1

Adding these lines solves the problem:

\renewcommand\pgfsetupphysicalpagesizes{%
  \pdfpagewidth\pgfphysicalwidth\pdfpageheight\pgfphysicalheight%
}

Credit to Tomáš Janoušek, who provided the answer in this post to the XeTeX mailing list: http://www.tug.org/pipermail/xetex/2009-June/013325.html.