What is the proper way to enable character protrusion in xelatex?

Question

I am using XeTeX 3.1415926-2.2-0.9997.4 (part of TeX Live 2010). One of its new features is character protrusion, and I would like to use it in my documents. The problem is that I cannot make it work.

XeTeX sample from xetex.tk wiki compiles correctly and displays protruded characters. Although XeLaTeX file that I created does not show any protrusion at all.

Can anybody please tell what am I doing wrong?

\documentclass[12pt]{book}

\usepackage{xltxtra}
\usepackage{polyglossia}

\setmainfont[Mapping=tex-text]{Charis SIL}
\setmainlanguage{english}

\def\setprotcode#1{
    \rpcode#1 U"0021    55
    \rpcode#1 U"002C    194
    \rpcode#1 U"002D    233
    \rpcode#1 U"002E    194
    \rpcode#1 U"003B    138
    \rpcode#1 U"003A    138
    \rpcode#1 U"003F    94
    \lpcode#1 U"2018    194
    \rpcode#1 U"2019    194
    \lpcode#1 U"201C    250
    \rpcode#1 U"201D    250
    \rpcode#1 U"2013    150
    \rpcode#1 U"2014    200
}

\XeTeXprotrudechars=2
\font\f = "Charis SIL:mapping=tex-text"
\setprotcode{\f}

\begin{document}

In a genetic algorithm, a population of strings (called chromosomes or the
genotype of the genome), which encode candidate solutions (called individuals,
creatures, or phenotypes) to an optimization problem, evolves toward better solutions.
Traditionally, solutions are represented in binary as strings of 0s and 1s, but other
encodings are also possible. The evolution usually starts from a population of randomly
generated individuals and happens in generations. In each generation, the fitness of
every individual in the population is evaluated, multiple individuals are
stochastically  selected from the current population (based on their fitness),
and modified (recombined and possibly randomly mutated) to form a new population.
The new population is then used in the next iteration of the algorithm. Commonly,
the algorithm terminates when either a maximum number of generations has been produced,
or a satisfactory fitness level has been reached for the population. If the algorithm
has terminated due to a maximum number of generations, a satisfactory solution may or
may not have been reached.

\end{document}

Answer 1

Oh well, disregard this, I'm stupid. I forgot to add microtype style file for Charis, which is referenced at the same wiki page.