Mixed button set mis-aligned in IE

Creating a buttonset containing buttons and checkboxes causes the elements to be misaligned in Internet Explorer 7 & 8.

For example:-

	<script type="text/javascript">
	$(function () {
		$("#buttonset").buttonset();
	});
	</script>
		
		<div id="buttonset">
			<button>Button 1</button>
			<input type="checkbox" id="button-2" /><label for="button-2">Button 2</label>
			<button>Button 3</button>
		</div>

In Firefox and Safari the three buttons are aligned. In Internet Explorer the middle button is lower than the other two and is overlapped by the third button. As a work-around I've added style="top:-2px;padding:2px 0px;margin:0px;" to the label element. Curiously this seems to work perfectly on the "toolbar" button demo but copying that code I had the same problem as above.