[lltx] unicode-math: [range=…] in-document

[Arno Trautmann]

Hi all,

the following document throws an error:

\documentclass{minimal}
\usepackage{unicode-math}
\setmathfont{Latin Modern Math}
\begin{document}
\setmathfont[range=\oiint]{XITS math}
\[ ∫ \oiint\]
\end{document}

./test.tex:7: Missing number, treated as zero.
<to be read again>
                    \oiint
l.7 \setmathfont[range=\oiint]{XITS math}

?

It works fine if the second \setmathfont is in the preamble. (I want to 
change the math font for some glyphs only in the document, so I cannot 
put it in the preamble.)
Is it not possible in prinicple to load a range of a math font 
in-document or is it a bug? Maybe something with parsing 
numbers/arguments in the preablem vs. in-document?

cheers
Arno