XML PI's (which is almost what this is) have two properties: target and data. For instance,
<?php echo("Hello World") ?>
The target is "php" and the data is 'echo("Hello World") '. Note the final space at the end of the data string.
Mozilla and Netscape don't themselves always expose <?xml-stylesheet ?>, particularly when the type pseudo-attribute equals "text/xsl". So be aware of that.
As for ASP itself... I'm clueless there.