Ive just had to do this hack to integrate web_store with
Wolrdpay.
 
In the web_store_order_lib.pl file
simply replace the display_order_form subroutine with the below.
Replace your own store name and staging server details,
backgournd colours etc......
 
#################################################

sub display_order_form {

################# World Pay Integration Hack for TSN

print qq~




~;

&display_cart_table;

print qq~







   ~;

   open (CART, "$sc_cart_path") ||
         &file_open_error("$sc_cart_path",
                 "Send to WorldPay", __VIRTUAL__, __LINE__);

   while ()
     {
   chop;

     @cart_fields = split (/\|/, $_);
     $cart_row_number = pop (@cart_fields);
     $quantity = shift (@cart_fields);
     $item_code = shift (@cart_fields);
     $description = shift (@cart_fields);
     $cost = shift (@cart_fields);

     $item_number = $cart_row_number - 100;

print qq~
<input type="hidden" name="code$item_number" value="$item_code">
<input type="hidden" name="desc$item_number" value="$description">
<input type="hidden" name="cur$item_number" value="GBP">
<input type="hidden" name="cost$item_number" value="$cost">
<input type="hidden" name="qty$item_number" value="$quantity">~;

    } # end of while cart

print qq~
<input type="submit" value="Click here to Submit your payment details">
</form>
</center>
</body>
</html>

~;
 
 
   close (CART);
 
} # end of display_order_form
 
###########################################################