Hi,
HTML templates of the user level interface are placed here:
/usr/local/cwpsrv/var/services/users/cwp_theme/original/
Look at the files called:
mod_email*
mod_forwarders*
mod_mail*
Most likely the modified files will be replaced by the original files once CWP is updated. So it is better to copy the theme files to another folder and modify the files there.