CSS - Get The Mouse-over Image To "stick"/stay Active?

i have a menu bar in my master page that is made up of 4 hyperlinks with background images that are being set using css. on hover-over, these images are swapped out, also by css. so each menu item (hyperlink) has two images, a static image and a hover-over image. when a user clicks one of the menu items and is taken to that page, i would like that hover-over image to "stick" for that page. here's my code:

<div id="nav">
<asp:HyperLink ID="hlHome" runat="server"
NavigateUrl="~/Default.aspx" CssClass="menuHome" />
</div>
#nav a, #nav a:visited
{
height:39px;
border:none;
padding:0;
display:block;
cursor:pointer;
}
a.menuHome, a.menuHome:visited
{
width:76px;
height:39px;
background:url('home.gif');
}
a.menuHome:hover, a.menuHome:active
{
width:76px;
height:39px;
background:url('home_hover.gif') no-repeat;
}

my hyperlinks background images are rendering, the mouse-over effect works too, i just can't get the mouse-over image to "stick"/stay active.