I'm trying to use the β character in a LaTeX document, but the output PDF never shows it. I am building with xelatex. From the following code:

```
\documentclass{article}
\usepackage{fontspec,xltxtra,xunicode}
\usepackage{textgreek}

\title{Beta Test}
\begin{document}
\maketitle

% UTF-8 beta and \textbeta don't show in the output.
β    
\textbeta

% However, UTF-8 delta and \textDelta work fine.
Δ
\textDelta

\end{document}

```

My output will only show the two Δ characters. So UTF-8 and `textgreek` seem to be fine, except for beta?