NO, php flags can not be set in the .htaccess file as an override. you must request a default copy of the php.ini file to be placed in your directory for making php program changes.
update Mar 2013: You no longer need a custom php.ini file you can set your own settings using the php selector tool. See this KB article on how to do it.
http://www.ethicalhost.ca/manager/knowledgebase.php?action=displayarticle&id=74 (login required)
