I have posted this in a different thread/section and it was answered (incorrectly?) or ignored. Anyway, I am looking at how to override the header_php.php file for a specific page. The file resides in modules>pages>page_name_folder>header_php.php. I have tried to add MY_TEMPLATE on each directory level with the new header_php.php file, but it never seems to be read. Can someone point me to where to put the new file so I can override it?

I have tried using (for the checkout_confirmation for instance)
includes\modules\MYTEMPLATE\pages\checkout_confirmation
includes\modules\pages\MYTEMPLATE\checkout_confirmation
includes\modules\pages\checkout_confirmation\MYTEMPLATE
includes\templates\MYTEMPLATE\checkout_confirmation

Any help is appreciated.