asp.net mvc 3 - Adding value to submitbutton with image -

i have problem :
have submit button defined follows :

 <input  type="submit" name="actionname" value="search" />  <input  type="submit" name="actionname" value="new" /> 

both submit buttons included in ajax beginform:

@using (ajax.beginform("pfsearch", "payer", ajaxoptions)) 

in controller ... based on actionname string provided .. different actions based on value of button pressed within ajax befin form :

if (actionname="search") { //do } 

and works charm .. until want add want add image class of submit button :

  <input class="search" type="submit" name="actionname" value="search" />   <input class="search" type="submit" name="actionname" value="new" /> 

my search tab looks :
can see main impediment adding value ... text appears on image.
how can make button act differently within ajax begin form considering giving value buttons doesn't work ? alternatives or workarounds appreciated. !

can please give link project's demo? , try use margin, padding , background-position:center;