call for price when product value is zero

Hi Guys..,

My customer has a few items in his product range where the prices change very quickly, so he would like to change the value to zero and have the ubercart display "Call for price" instead of the zero value; also the "add to cart" button should be disabled.

I have been looking into this and trying various solutions for the past 3 days with some success...

I would prefer to create a module...see below.. rather than a theme mod.

I have found some code.. (I will credit the person who wrote it when I find it again)

The code uses the nodeapi to change the product display which works fine, but the product grid still shows the £0.00 and the "add to cart" button. I have tried various things to try and change the product grid but no joy...

the code...

// $Id$

/**
 * @file
 * uc_acsCall4Price.module
 * Ubercart where the product has a zero value display call for pricing
 */
 /**
* Implementation of hook_nodeapi()
*/
function uc_acsCall4Price_nodeapi(&$node, $op, $a3 = NULL, $a3 = NULL, $a4 = NULL){
  //This bit works and changes the product display
  
  if ($op == 'view' ){
    if ($node->type == 'product' ){
      //drupal_set_message("uc_acsCall4Price_hook_node here..","status")
      if (intval($node->sell_price)==0) {
        $node->content['sell_price']['#value'] = "<div class=\"call-for-pricing\">Call for pricing</div>";
        $node->content['display_price']['#value'] = "<div class=\"call-for-pricing2\">Call for pricing</div>"  ;
        unset($node->content['add_to_cart']) ;   // remove add to cart button
      }
    }
	
	//  this is an attempt to change the grid display
	if ($node->type == 'category' ){
      //drupal_set_message("uc_acsCall4Price_hook_node here..","status")
      if (intval($node->sell_price)==0) {
        $node->content['sell_price']['#value'] = "<div class=\"call-for-pricing\">Call for pricing</div>";
        $node->content['display_price']['#value'] = "<div class=\"call-for-pricing2\">Call for pricing</div>"  ;
        unset($node->content['add_to_cart']) ;   // remove add to cart button
      }
    }
  }
  
}

The first part works, the second to try and change the grid display does not work.

Again I have tried various things... including trying to hook into **function uc_catalog_nodeapi**

and a dozen other approaches...

So, anyone know how I can access the grip product view similar to the first section of the code that works.

Hope this makes sense... I'm a little frustrated with all of the reading i have been doing and going around in circles...

Many thank for looking and I hope someone can help.

Regards

Steve