httpd.conf is like the php.ini but for apache
it is higher up in the chain than .htaccess. so if a directive is only changeable via httpd.conf then htaccess wont work.
safe mode has no bearing on whether you can use htaccess or not. but that doesnt mean your host allows you to use htaccess, as they controll that from httpd.conf
it would be very simple to just try to do it and see if it works.
php_flag register_globals off # i am a comment