verticle alignment with CSS can be tricky since it will not be treated the same in all browsers.
one way to accomplish this for most modern browsers is to add;
display:table-cell;
vertical-align:middle;
to the ul#cssmw > li > a selector in the CSSMenuWriter/cssmw/menu.css file:
ul#cssmw > li > a {
background-color: #819D40;
background-image: none;
color: #FFFFFF;
display: block;
font-family: Georgia, "Times New Roman", Times, serif;
font-size: 14px;
font-style: normal;
font-weight: normal;
height: 40px;
margin: 0 0 0 0;
padding: 0px 0px 0px 0px;
text-align: center;
text-decoration: none;
text-transform: uppercase;
width: 87px;
display:table-cell;
vertical-align:middle;
}
You can read about other techniques for vertical centering here:
vertical-centering-with-css/