RV accounting doc number on invoice form

hello, friends.

in standard SAP, the default settings (requirements) for invoice output type RD00 is that the output is created automatically (assuming all condition records have been set) upon posting of the invoice to FI.

my questions:

1. on the requirement, does the system read the status of the invoice (i.e. "complete") or does it confirm the existence of the RV accounting doc?

2. is it possible that upon output creation in the invoice upon saving, that the accounting doc number can already be retrieved and included in the invoice form, further allowing printing upon saving?

on question #1, is it possible to have the invoice "posted" to FI without an accounting doc as a consequence of the system dumping? i think this is unlikely. i also think that, in general, the difficulty is more in trying to get a subsequent document that has yet to be created as an additional detail for a current form. unless there is any userexit that may help achieve this?

many thanks for your inputs!