[XeTeX] bidi, math, and amstext

[maxwell]

Not sure if this is the appropriate place to say this, but: I seem to 
have found a problematic interaction (aka bug?) between the bidi package 
and the amstext package.

Here's a minimal example:

--------------------
\documentclass{report}
\usepackage{fontspec}
\usepackage{biblatex}
\usepackage{amstext}
\usepackage{bidi}

\begin{document}

V $_{\text{[high, low]}}$

\end{document}
------------------

I would of course expect the words "high" and "low" to come out in that 
order in the PDF.  Instead, they come out in reverse order, something 
like
     low] [high,
If I leave out the fontspec package in the above code, the resulting 
output is even stranger:
     ]wol ,hgih[

I'm not sure why it's necessary to load the biblatex package in the 
above, but if I don't then xelatex complains:
     ! Undefined control sequence.
     l.3 \abx at aux@sortscheme
                        {nty}


     Mike Maxwell
     University of Maryland