[otrs] OTRS is sending email with empty "MAIL FROM:<>"

Hello All! I have a problem with OTRS since messages that are sent from OTRS to list admins and users are not coming through. I have debuged problem down to the fact that when OTRS (2.2) sends email it doesn't correctly set MAIL FROM header in SMTP connection. OTRS sends the email with "MAIL FROM:<>" instead of something like "MAIL FROM:". This mail is then rejected by mailer since it has empty sender field. I did recheck my OTRS settings and I have setup email addresses for sending out. Am I missing a parameter in OTRS or is this intended to be in such way!? BR, Alen