dumb question re tab positions

Being new to CSS and PhP (but doing okish so far!) I've came across a weee problem.

Ive been messing with the css properties for the text over the tabs, to drop them down a bit.

The text moves, but the tab images dont!

How do I drop the tab images which are set as the background  please?

#header .b a {
background: url('../image/tab.png');
behavior: url('catalog/javascript/png/iepngfix.htc');
width: 100px;
height: 19px;
padding-top: 70px;
color: #00FF00;
text-align: center;
text-transform: uppercase;
text-decoration: none;
float: left;
display: block;
margin-left: 2px;
cursor: pointer;
background-repeat: no-repeat;
max-height: 19px;

done it

#header .b {
position: relative;
top: 102px;
float: right;