LuaLaTeX, fontspec and tracking with microtype

Question

I try to get microtype's tracking working but without success: up-to-date TeXlive 2011 (lualatex 0.70.1) with microtype v2.5 beta 07. Sample code:

\documentclass{article}
\usepackage[no-math]{fontspec}
\usepackage[tracking,letterspace=500]{microtype}
\begin{document}\parindent0em

\fontspec[SmallCapsFont={Latin Modern Roman Caps}]{Latin Modern Roman}
\textsc{stealing sheep}

\fontspec{Linux Libertine O}
\textsc{stealing sheep}
\end{document}

Latin Modern works fine (letterspaced small caps) but not Libertine (letterspaced lowercase letters). The only difference between both fonts is that Latin Modern has small caps in a separate file. Any ideas how I could get the same working for Libertine? The following does not work, however:

\fontspec[SmallCapsFont={Linux Libertine O}]{Linux Libertine O}

Nor does:

\fontspec[SmallCapsFont={Linux Libertine O},SmallCapsFeatures={Letters=SmallCaps}]{Linux Libertine O}

Any suggestions are very welcome.

Edit: the following does work (with side effects, see below):

\fontspec[Renderer=Basic]{Linux Libertine O}

2nd edit: See related question.

Answer 1

This is due to a bug (or, if one were more polite: incompatibility) in luatex. I've just reported it on the luatex list.

Edit: ... and I got an answer, persuading me to be more polite, indeed - it's not a bug but microtype's using a legacy command.

The simple solution is: load the fonts with Renderer=Basic (side effects are yet to be discovered).

Answer 2

\documentclass{article}
\usepackage[no-math]{fontspec}
\fontspec[SmallCapsFont={LinLibertineCapitalsO},
          SmallCapsFeatures={Letters=SmallCaps}]{Linux Libertine O}
\usepackage[tracking,letterspace=500]{microtype}
\begin{document}\parindent0em

stealing sheap

\textsc{Stealing Sheep}

\textls[800]{\scshape Stealing Sheep}

\end{document}