hide price when CALL FOT PRICE

hello everyone, this is my project. I offer installations which vary in prices, and would not like to show price of those to my potential clients, but just a CALL FOR PRICE button.

at the same time, i'll be using google merchant plugin to list my products, including the installations on the google shopping website.
problem is that when a product is CALL FOR PRICE the google plugin won't read it, so, just for the time it takes me to make the feed, i would back up my database without the call for price items, so they will all get listed. then, after the feed is produced, i would upload a back up of the database with the call for price products. i know, it will be a pain, but until i find a better solution that's gonna be the way.

what i'm looking for is a way to completely hide the prices from the product page when a product is make as call for price.
i'm aware that if i put the price to 0 it will not show, but it will take me more time to adjust all the prices every month or so.

I found what it was at the time a solution, but is is dated 2008 so it did not work.

from the post

Edit /includes/modules/your_template/product_listing.php around line 107:
PHP Code:

case 'PRODUCT_LIST_PRICE':
$lc_price = zen_get_products_display_price($listing->fields['products_id']) . '<br />';
$lc_align = 'right';
$lc_text = $lc_price;

    // more info in place of buy now
    $lc_button = ''; 

Change to:
PHP Code:
case 'PRODUCT_LIST_PRICE':
$lc_price = zen_get_products_display_price($listing->fields['products_id']) . '<br />';
$lc_align = 'right';
$lc_text = ''; //$lc_price; //disable price display

    // more info in place of buy now
    $lc_button = '';  

http://www.zen-cart.com/showthread.php?109078-Remove-Price-from-Product-Listing-but-Keep-Buy-Now-Button

i tried this in both the product_listing.php i found on my site (i'm using the Numinix template) but price still shows.

anybody can help?

many thanks

For clarity, the current process described (upload all but the call for price items), update the google feed, then upload call for price products, what's the reason again? From what is described it appears that google merchant won't receive anything regarding a product that is call for price, also the process doesn't seem to imply that upon the next update that the existing call for price items are removed. So somewhat trying to figure out what the real goal is. Ask that because also the discussion (even though I've read it three times) seems to imply that when trying to make a product call for price the price is both hidden and displayed.

Perhaps with a little more clarification some assistance can be offered? (Suggest reviewing the posting guidelines in case there is some info not yet provided that would help with answering.)

Ok, now I have a full list of products listed on Google shopping. They are there with prices. But now that Google crawled my site and listed the products, I would like to switch the installations products back to call for price, so potential clients would have to call in to book. Price is only to give an idea of the cost, normally installations are bespoke prices. I'm listing the installations on Google shopping only for marketing and visibili, not really for selling them directly to the public.

But when I switch the 10 or so installations to call for price I would like the price of those products not to show in the product page, because unless the price is set to 0 even if the listing is call for price, the price will anyway show. Hence the code above, which unfortunately did not work. . Is that doable?