How to write package that will use batch source and generate transaction number

Guru's

I have developed a package that has two procedures. One to load AR transaction data in a staging custom table and a second procedure to import the data from the custom staging table into the interface tables.

With this I have developed an integrator that allows me to load the data into the staging table. This part of the package works well. It is to be noted that my batch source I am using is setup to do autonumbering for the transaction number.

My issue is I dont know how to deal with the numbering aspect in the second part of the package? The package I have is for when you actually have to specify a transaction number so I need to change the procedure to cater for the autonumbering batch and this is where I am facing a problem. How to achieve this??