There is currently no way to enter two different credentials for the same account in the same account entry in osT.  That being said... I think that you can trick the system by setting up two different emails in osT.  Note: I have not tried to do this, but it "should" work. :)1. Admin panel -> emails2. add Inbound emailAdd New EmailEmail Address: inbound@domain.extemail Name: Inbound(select new ticket settings)username the username for polling.password the password for polling.Configure the Fetching Email via IMAP or POP settings for the account.Click Save Changes.3. add outbound emailAdd New EmailEmail Address: outbound@domain.extemail Name: Outbound(select new ticket settings)username the username for SMTP.password the password for SMTP.Leave Fetching Email via IMAP or POP blankConfigure the Sending Email via SMTP settings for the account.Click Save Changes.4. Go to Admin panel -> Settings -> EmailsSet the Default System email to your OUTBOUND.Click Save Changes.5. If you made any Department level email changes you would want to set those to the outbound that we just made.Some notes: this is presuming that your using a very simply email setup.  Other wise you may need to add additional OUTBOUND addresses.  But I think that this will help.