Thanks yama
For some reason insert image/hyperlink aren’t working in Firefox (4.0 nightly) or Opera with this alpha. The RTE doesn’t show at all in IE9.
However, I have worked out how to integrate KCFinder in case anyone finds it useful. In functions.php, replace
$ckInstances .= "filebrowserBrowseUrl : '" . $mcpuk_path['base'] . "'," . PHP_EOL;
$ckInstances .= "filebrowserImageBrowseUrl : '" . $mcpuk_path['image'] . "'," . PHP_EOL;
$ckInstances .= "filebrowserFlashBrowseUrl : '" . $mcpuk_path['flash'] . "'," . PHP_EOL;
with
$ckInstances .= "filebrowserBrowseUrl : '" . '/assets/plugins/kcfinder/kcfinder/browse.php?type=files' . "'," . PHP_EOL;
$ckInstances .= "filebrowserImageBrowseUrl : '" . '/assets/plugins/kcfinder/kcfinder/browse.php?type=images' . "'," . PHP_EOL;
$ckInstances .= "filebrowserFlashBrowseUrl : '" . '/assets/plugins/kcfinder/kcfinder/browse.php?type=flash' . "'," . PHP_EOL;