SRM table for messages

Hi,

I'm looking for the table in SRM wich contains the output messages with regard to Po's. I found that SRM does contain table NAST similair to R/3, however when I look into it, it isn't populated. The NAST table in R/3 only shows info for PO's that were created locally. I'm a BI consultant who is looking for the medium and date of PO output messages.

Greetz