Problems with .htaccess in virtual host

Hi all!
I fall into a problem like this:
I Install ISPConfig following the post: http://www.howtoforge.com/perfect-server-centos-5.3-x86_64-ispconfig-2-p6
Everything work fine!
But some day, my customer asks me “ How to do safe mode off in his website”

First, I simply think “ make a .htaccess file with directive php-flag safe_mode off, then place in web root folder of this site, but seemly it doesn’t work. Phpinfo() show safe mode = on at both Local and Master Value. File .htaccess work very well for rewrite rules. I change php_flag directive into php_admin_flag, then server report Internal Server Error, website doesnot work

From my knowledge, in think, perhaps I’m using suPHP because in the httpd.conf, there is a directive LoadModule suexec_module modules/mod_suexec.so but not any mod_php though both modules was complied (httpd -t -D DUMP_MODULES). But in the config.inc.php, I’m using $go_info["server"]["apache2_php"] = 'addtype' not suphp, and I still chmod 777 for files and folders, this action is as opposed to suPHP methods

So, in the Vhosts_isponfig.conf, I change php_admin_flag safe_mode Off, restart apache. OK, at this time, phpinfo() show Safe_mode = off but open_basedir and the rest of directives is removed automatically, this was dangerous. Half a day, System automatically set Safe_mode=On and restore all directives before

So, who can tell me what php methods I’m using, can I use .htaccess file to do safe_mode off for each website? and explain me directive $go_info["server"]["apache2_php"] = 'addtype’? filter? engine?
Many thanks!!