I do not receive bounces
There is some explanation here that you have probably already read http://book.civicrm.org/user/current/advanced-configuration/email-system-configuration/

Note it says: "The local part is optional and only relevant if you were able to set up an account using sub-addressing. It should be the account you created with '+' or '-' appended , e.g., "return+" or "return-"."

I see you have 'bounce' in that field which may be your problem