What about just putting the buttons into a div with properties display:none; and then switching it with JS to display:block;?

Shouldn't it work like this:

<div id="jsbuttons" style="display:none;">
<!-- JS Buttons... -->
</div>
<script type="text/javascript">/* <![CDATA[ */
document.getElementById('jsbuttons').style.display="block";
/* ]]> */</script>
<noscript>
<!-- Non JS explanations...... --> 
</noscript>

EDIT:
Now implemented here for testing.