automatic creation of billing document

Hi all,

i want to automate creation of billing document for all the deliveries for which PGI done.

i think we have to define a job which will call VF04.

my question is when we do VF04 manually, we have to give selection criteria like sales org etc and then it displays the list of all the deliveries and then we have to select the deliveries manually and press collective billing/individual billing.

so when the batch job calls the VF04, how will the batch job tells VF04 to select all deliveries and generate the invoices.

regards

sachin