Thanks Suneet and Seegal. Yes, I've seen RSNAST00 too, and one can execute SD70AV3A in background too. My main beefs with the offered functionality are:
- there seems to be nothing persisted anywhere that could be called "SD Invoice Output Run" - something that says: on so and so date and time, with such and such parameters, so and so executed invoice output run, which processed these Invoices;
- so far as I can see, the NASTy protocols are not persisted as Application Logs, so I think I can't easily set up EMMA/BPEM exception/clarification case processing for these processes (FM WFMC_PROTOCOL_SHOW does transform the protocols to Application Log temporarily, to display popup; FM CM_F_TRANSFER_INTO_APPL_LOG has no static uses in our system)
And the one thing to expect during mass output in my experience is exceptions and the need for clarification - lots of it. There may perhaps be ways how I could program own logic to get EMMA/BPEM to work on NAST stuff, but then I could of course try to program the whole SD invoice output application from scratch as well...
I may be too used to IS-U/FI-CA way of doing things and/or too impatient in expectting the results after looking at stuff for couple of days, but I expect any "Mass Activity" to result in an identifyable and persisted "Run", which lets to to see the start parameters, the stuff it processed and the Application Logs (no, SM37 Job is only a poor replacement for that). The self-learning process for SD output processing seems to be very difficult... my initial (and perhaps too hasty impression) of the functionality is - this is "stone-age" 
. I've reacquired lots of respect for IS-U/FI-CA developers form looking at SD Invoice output and now think that it was a collosal mistake not to try to integrate SD billing documents into IS-U Invoicing...
Thanks again and cheers
Janis