Change Attachment name and EMAIL Subject in SAP document

Hi Experts,

I have multiple queries for the background job creation:

In sm36 i am creationg one job with list of external or internal receipients:

so the attachment goes in SAP inbox( if user is internal) or User Mailbox (If user is external).

1- When User is internal means mail goes to SAP Inbox::

Please check the below pic:

a) How to increase that expiration date on the mail.

b) How to change Email-subject of the mail, this is same as job name

c) How to change attachment name , this is same as job name.

d) Also suppose a job is already created by user, now can we add receipients list later to this scheduled job?

2- When User is External means mail goes to User Inbox::

A) How to change name of email subject and attachment.

Regards,

A. Trivedi