When adding a manual transaction in DFWorks you can change the default mailrun ID to a user generated mailrun ID.
1. From the Add Transactions screen you will notice that the Mailrun field defaults to Show Existing.
2. Once you select your Job Type, click on the Use Default radio button and it will populate the Mailrun field with a number starting with an M-xxxxxx.
3. If you click in the Mailrun field you can overwrite what is there and type in your own mailrun.
When finished entering all of the required information, the transaction can be saved.
UPDATED: April 12, 2017