Redirect "call for price" to custom page?

Apologies if this is a silly question, but I've created a custom contact form outside of the ZC system that I want to send users to when they click on a "Call for Price" link inside the shopping cart. I've figured out how to change the words "Call for Price", but I can't seem to figure out where to define the URL that is being generated. Using the developer's toolbox wasn't helpful.

Thanks in advance,
--Gianna

I answered my own question. I changed the following line in /includes/functions/functions_general.php from

$return_button = '<a href="' . zen_href_link(FILENAME_CONTACT_US) . '">' . TEXT_CALL_FOR_PRICE . '</a>';

to

$return_button = '<a href="http://mydomain.com/contact.html">' . TEXT_CALL_FOR_PRICE . '</a>';