I am currently working on a project where I am accessing an e-mail account using PHP\'s imap_open(). I know that I can send an e-mail with PHP using the mail() function.
This is more to email account setting to save the email sent to sent account folder.
You may try with external mail that already configured to save email sent to sent folder e.g Gmail http://www.vulgarisoip.com/files/phpgmailer.zip
example :
require_once('/phpgmailer/class.phpgmailer.php');
$mail = new PHPGMailer();
$mail->Username = 'user@domain.com';
$mail->Password = 'password';
$mail->From = 'user@domain.com';
$mail->FromName = 'User Name';
$mail->Subject = 'Subject';
$mail->AddAddress('myfriend@domain.com');
$mail->Body = 'Hey buddy, here\'s an email!';
$mail->Send();