How to use file encoding?

Example:

$set{HTML}
{
<html>
<head>
<meta name="content-type" content="text/html; charset=$system.sw.getOSFileEncoding{}" />
...
</head>
<body></body>
</html>
}

$// ~~~ write HTML file to disk ~~~
$if{$io.exists{$get{protocoll}$get{path}/index.html}}
       {$io.rewrite{$get{protocoll}$get{path}/index.html}{1}{$encodeString{$get{HTML}}{$system.sw.getOSFileEncoding{}}}}
       {$io.write{$get{protocoll}$get{path}/index.html}{1}{$encodeString{$get{HTML}}{$system.sw.getOSFileEncoding{}}}}