Get the latest PHPMailer package (http://sourceforge.net/projects/phpmailer/files/phpmailer%20for%20php5_6/2.2.1/phpMailer_v2.2.1_.tar.gz/download(http://sourceforge.net/projects/phpmailer/files/phpmailer%20for%20php5_6/2.2.1/phpMailer_v2.2.1_.tar.gz/download)), unpack it and copy the files class.phpmailer.php, class.smtp.php and the language file you would like to use (there's a lot of them inside the languages dir of the PHPMailer package, in my case I copied the phpmailer.lang-br) to the osticket include dir.

Now, change some files:

File: include/class.phpmailer.php

Add this include at the top of the file:

include_once('class.smtp.php');

File: include/class.email.php

Add this include at the top of the file:

include_once(INCLUDE_DIR.'class.phpmailer.php');

Change the code under the if $(smtp) clause (#send method):

if ($smtp) {

$from = $this->getEmail();

$fromname = $this->getName();

$subject = stripslashes(preg_replace("/(\r\n|\r|\n)/s",'', trim($subject)));

$to = preg_replace("/(\r\n|\r|\n)/s",'', trim($to));

$headers = array('Message-ID' =>'<'.Misc:(6).''.time().'-'.$this->getEmail().'>',

'X-Mailer' =>'osTicket v 1.6'

);

$body = stripslashes(preg_replace("/(\r\n|\r)/s", "\n", trim($message)));

$body = eregi_replace("",'',$body);

// PHPMailer

$mail = new PHPMailer();

$mail->SetLanguage('br', INCLUDE_DIR);

$mail->IsSMTP();

$mail->IsHTML(False);

$mail->CharSet = 'UTF-8';

$mail->From = $from;

$mail->FromName = $fromname;

$mail->Subject = $subject;

$mail->AddAddress($to);

$mail->AddReplyTo($from, $fromname);

$mail->AddCustomHeader('Message-ID:'.$headers);

$mail->AddCustomHeader('X-Mailer:'.$headers);

if($attachment && $attachment && is_readable($attachment)) {

$mail->AddAttachment($attachment, $attachment, 'base64', $attachment);

}

$mail->Host = $smtp;

$mail->SMTP_PORT = $smtp;

$mail->SMTPAuth = $smtp ? true : false;

$mail->Username = $smtp;

$mail->Password = $smtp;

$mail->Timeout = 20;

$mail->SMTPDebug = False;

$mail->SMTPSecure = 'tls';

$mail->Body = $message;

if ($mail->Send()) return True;

$alert = sprintf("Unable to email via %s:%d \n\n%s", $smtp, $smtp, $smtp);

Sys:(LOG_ALERT,'SMTP Error', $alert,false);

}

Change the code under the if(!$errors && $vars) clause (#save method):

if(!$errors && $vars) {

// PHPMailer

$mail = new PHPMailer();

$mail->SetLanguage('br', INCLUDE_DIR);

$mail->IsSMTP();

$mail->Host = $vars;

$mail->SMTP_PORT = $vars;

$mail->SMTPAuth = $vars?true;

$mail->Username = $vars;

$mail->Password = $vars;

$mail->Timeout = 20;

$mail->SMTPDebug = False;

$mail->SMTPSecure = "tls";

if ($mail->SmtpConnect()) {

$mail->SmtpClose();

}

else {

$errors = '<br>Unable to login. Check SMTP settings.';

$errors = '<br>'.$mail->ErrorInfo;

}

Everything is working (for me) now (SMTP + Gmail).

PS: I'm not a PHP programmer, if there's one better way to do this, please let me know.