XSLT Processing w/ Embedded PHP Strips Trailing '?' of

If I run xsltproc from libxslt-1.1.11 on some xml w/ processing
instructions in it, the closing '?' gets removed. Is this legit or am
I missing something?

Mike

INPUT:

<tr><td>Username:</td>

<?php
        if ($set != 0 && ($set & 0x01) == 0) {
                echo "<td bgcolor=\"#ff0000\">";
        } else {
                echo "<td>";
        }
        echo "</td><input type=\"username\" name=\"username\" value=\"" . $username . "\"/>";
?>

OUTPUT:

<tr>
<td>Username:</td>

<?php if ($set != 0 && ($set & 0x01) == 0) {
        echo "<td bgcolor=\"#ff0000\">";
    } else {    
        echo "<td>";
    }
    echo "</td><input type=\"username\" name=\"username\" value=\"" . $username . "\"/>";