smtp $params["localhost"] does not supported

What steps will reproduce the problem?
1. Add [email_smtp] section to PEAR_DIR/data/Xinc/xinc.ini
2. Add localhost=some.server
3. Receive mail from Xinc 

What is the expected output? What do you see instead?
WIE: Email header has envelope-from <Xinc@some.server>
WIS: Email header has envelope-from <Xinc@localhost>

What version of the product are you using? On what operating system?
2.0.0b145

Please provide any additional information below.
It is a problem, because mail server can reject emails or froze them (as I got)

Original issue reported on code.google.com by kingo...@gmail.com on 6 Mar 2008 at 9:39

Tiger66639 / xinc

smtp $params["localhost"] does not supported #138