Hi,
The mail goes to the Bulk Folder because the your mail provider detected it as spam. If the mail does not come from a listed Mail Server, it is usually considered as spam.
http://dsbl.org/main
http://www.spamhaus.org/xbl/
check these links, if your IP is present in their database, some servers might not even accept the mail.
So, one thing you can do is get your SMTP server registered there.