Try this, it works for me..
This works for email but I'm not sure if something different needs to be done for the text message.
$header = "MIME-Version: 1.0\r\n";
$header .= "Content-type: text/plain; charset=iso-8859-1\r\n";
$header .= "Reply-To: [email]johndoe@johndoe.com[/email]\r\n";
$header .= "From: John Doe<johndoe@johndoe.com>\r\n";
Then of course make sure the headers are being passed to the mail function.