The only php method that seems to work is cgi
Looking at /usr/local/ispconfig/server/conf/vhost.conf.master
I noticed that only the standard php method includes the open_basedir paths.
I put the following lines in vhost.conf.master under the cgi method and then set the path string to "none"
That is the only thing that seems to work
php_admin_value sendmail_path "/usr/sbin/sendmail -t -i -fwebmaster@<tmpl_var name='domain'>"
php_admin_value upload_tmp_dir <tmpl_var name='document_root'>/tmp
php_admin_value session.save_path <tmpl_var name='document_root'>/tmp
<tmpl_if name='security_level' op='==' value='20'>
php_admin_value open_basedir <tmpl_var name='php_open_basedir'>