Vertical Centring

I'm trying to create a horizontal navigation bar for the top of my page. I need to make each link in the bar 40px heigh and 75 wide to fit a background image to each link.

To do this I need to centre the text vertically to make it correctly line up. Currently I have this (I haven't added in any of the background images yet)

#navBar {
	margin: 0px;
	padding: 0px;
	width: 800px;
	clear: both;
	float: left;
}
#navBar ul {
	list-style-type: none;
	margin: 0px;
	padding: 0px;
}
#navBar ul li {
	border: thin dotted #000;
	height: 40px;
	width: auto;
	float: left;
}

But it just won't work!

All suggestions welcomed!

Andrew