[imp] escapeshellcmd() and popen() really needed?

[BiBe]

Hi,
i've confgigured safe_mode off in apache-webserver and alternatively using
open_basedir to restrict each user to his www-directory. To avoid him braking
out of his basedir, i've disabled a few shell-functions including 
escapeshellcmd() and popen() which are apparently used by IMP to compose and
send mails.
Is it possible to configure IMP not using these shell-functions?
Many thanks,
BiBe