Civi buildAmount Hook not getting called

[developer]

Hi All,
Im using Shopping Cart Style Event Registration. I've added 2 events to the cart and trying to check out.
in cart check out form(CRM_Event_Cart_Form_Checkout_ParticipantsAndPrices) the url is
http://192.168.2.28/mysite/index.php?option=com_civicrm&task=civicrm/event/cart_checkout.

On this form I'm trying to implement a hook called
hook_civicrm_buildAmount( $pageType, &$form, &$amount )

Civi is not calling buildAmount hook. I tried with other following GUI hooks, nothing seems to be called by Civi on this form.

function hook_civicrm_pageRun( &$page ){
function hook_civicrm_customFieldOptions( $fieldID, &$options, $detailedFormat = false ){
function hook_civicrm_dashboard( $contactID, &$contentPlacement = self::DASHBOARD_BELOW ){

is it for any purpose in Civi. if so, Can anyone please tell me how can I achieve buildAmount hook functionality??

Thanks in advance!!

[Erik Hommel]

You could try adding a hook to the CRM_Event_Cart_Form_Checkout_ParticipantsAndPrices? You can do this by making a call to CRM_Utils_Hook, check for example one of the simpler forms in CiviCRM?

[developer]

Thanks Erik, I'll try to do that.