[XeTeX] Bold digits and bold italic Greek using mathspec

[Derek Clegg]

Forgive me if this is not the best place to post questions about mathspec; if there's better place, let me know.

I'm trying to get bold upright Latin, bold digits and bold italic Greek to appear together using mathspec and MinionPro.

I've attached my test program below. The result I see is bold upright Latin (correct), bold upright Greek (incorrect), and normal upright digits (also incorrect). I've tried a number of things to fix this, all failures. Any suggestions would be appreciated.

Thanks,
Derek

\documentclass{article}
\usepackage{amsmath}
\usepackage{mathspec}
\usepackage{bm}

\setmainfont[Numbers = OldStyle]{Minion Pro}
\setmathfont(Digits,Latin,Greek){Minion Pro}
\setmathrm{Minion Pro}

\begin{document}

\newcommand{\vect}[1]{\boldsymbol{\mathbf{#1}}}

This is bold upright Latin, bold upright digits and bold italic Greek.
\begin{equation}
 \dot{\vect{x}} = \vect{v}(\vect{x}, \vect{\alpha}) \,,
 \vect{\alpha} \ne \vect{0} \,.
\end{equation}

\end{document}