WordPress Plugin, apply code highlight to the Syntaxhighlighter 1.5 style by Syntaxhighlighter Evolved.

syntaxhighlighter-for-legacy.php

<?php
/*
Plugin Name:  Syntaxhighlighter for Legacy
Description:  apply code highlight to the Syntaxhighlighter 1.5 style by Syntaxhighlighter Evolved.
Version:      1.0
Author:       makoto_kw
Author URI:   http://www.makotokw.com/
 */
function SyntaxhighlighterEvolvedForPlaneHtml($text) {
	global $SyntaxHighlighter;
	if (isset($SyntaxHighlighter)) {
		// Syntaxhighlighter 1.5 style
		$useLangs = array();
		if (preg_match_all('/name="code" class="([\w#-]+)/', $text, $matches)) {
			$useLangs = array_merge($useLangs, $matches[1]);
		}
		if (count($useLangs)) {
			foreach ($useLangs as $lang) {
				// Register this brush as used so it's script will be outputted
				$SyntaxHighlighter->usedbrushes[$SyntaxHighlighter->brushes[$lang]] = true;
			}
			$SyntaxHighlighter->useLegacy = true; // hack!
		}
	}
	return $text;
}
function SyntaxhighlighterLegacyScript() {
	global $SyntaxHighlighter;
	if (isset($SyntaxHighlighter) && $SyntaxHighlighter->useLegacy) {
?>
<script type="text/javascript" src="<?php echo plugins_url('syntaxhighlighter/syntaxhighlighter/scripts/shLegacy.js')?>"></script>
<script type="text/javascript">
	dp.SyntaxHighlighter.HighlightAll('code');
</script>
<?php
	}
}

add_filter('the_content', 'SyntaxhighlighterEvolvedForPlaneHtml');
add_filter('wp_footer', 'SyntaxhighlighterLegacyScript', 20);