Taking math operators from Unicode font, but chars from text

Question

since I've found a nice font (oldstandard), I'm doing my very first steps using XeLaTeX. This font has enough math operators for me, but unfortunately covers no mathmematical alphanumeric signs.

So using unicode math, I get the correct operators from the font, but no greek letters. When using mathspec, I get greek letters (which then origin from the greek text block), but the Computer Modern math operators instead of the Old Standard ones. How to get both symbols and letters from a font while mapping math greek to text greek letters?

MWE: This prints correct letters, but wrong symbols:

\documentclass[a4paper]{scrartcl}
\usepackage{mathspec}
%\usepackage{unicode-math}
\setmainfont{Old Standard TT Regular}
\setmathsfont(Latin,Greek,Symbols){Old Standard TT Regular}
%\setmathfont{Old Standard TT Regular}
\begin{document}
AV
\[
    A= \sum V\oplus\alpha^\varkappa
\]
\end{document}

Exchanging the commented lines with the line above respectively yields correct symbols but wrong letters.

Answer 1

You can do it with unicode-math:

\documentclass[a4paper]{scrartcl}
\usepackage{unicode-math}

\setmainfont{Old Standard}
\setmathfont{Old Standard}
\setmathfont[range=it]{Old Standard Italic}

\begin{document}
AV
\[
A= \sum_{i=1}^n V_i\oplus\alpha^\varkappa
\]

\end{document}

Answer 2

I doubt that is a good idea to use a text font as math font. A math not only need symbols but also quite a number of other information. Imho it is better to use as base a real math font and to exchange only single symbols with symbols from a text font.

\documentclass[a4paper]{scrartcl}
\usepackage{unicode-math}
\setmathfont{Latin Modern Math}
\setmathfont[range=up/{greek,Greek}]{Arial Unicode MS}
\setmathfont[range=it/{greek,Greek}]{Arial Unicode MS}
%Just to make sure that all math fontdimens are from a math font:
\setmathfont[range=\int]{Latin Modern Math}
\begin{document}

\[
    V\oplus V \quad \alpha^\varkappa \Gamma
\]
\end{document}