Adding a simple dropdown to MCE toolbar?

I’m trying to add a dropdown menu to the MCE editors via a plugin. Unfortunately, it is showing up with some strange placement/alignment:
http://i1270.photobucket.com/albums/jj612/hendridm/screenshot.png

This seems like it should be simple, but I’ve been racking my brains trying to figure it out.

I tried add_action(‘media_buttons’ …) and add_action(‘media_buttons_context’ …), but it always aligns strangely. I don’t care where the button is, per se. I just want it visible on both the Visual and HTML editors.

What am I doing wrong? Incidently, if I uncomment the /img/ua2.png button, it displays fine with correct alignment. Is there a better way to do this?

add_action('media_buttons','upsell_add_sc_select', 11);
function upsell_add_sc_select(){
    $include = array(1 => "Ad #1", 2 => "Ad #2"); //test array
    echo '<select id="upsell_add_select">&nbsp;<option>Upsell Ads</option>';
    foreach ($include as $key => $val){
    	$upsell_ad_id = explode("#", $key);
		echo '<option value="[upsellad id='.$key.']">'.$val.'</option>';
	}
	echo '</select>';
	//echo '<a href="#"><img src="/img/ua2.png" /></a>';
}

add_action('admin_head', 'button_js');
function button_js() {
	echo '<script type="text/javascript">
	jQuery(document).ready(function(){
	   jQuery("#upsell_add_select").change(function() {
			  send_to_editor(jQuery("#upsell_add_select :selected").val());
        		  return false;
		});
	});
	</script>';
}