Good point! Each of DIR’s corporation/nonprofit clients uses the portal of supplier information differently. Some use it primarily for searching/sourcing vs. ‘matchmaking’ or ‘RFP’ postings. Others integrate the entire portal and its reporting capabilities into their procurement system. The best people to ask about requisitions and postings are [employees of the Corporation].
Typically a real-person contact* for Supplier Diversity will be either listed on their sites, or in a regional directory (sometimes) available from regional divisions of supplier advocate groups including WBENC or NAWBO, NMSDC, GLCC, etc.. Otherwise, an email or phone call may yield results, too! (Old school, I know, but supplier diversity liaisons typically are open to email and phone conversations.)
*DIR does offer a database of Supplier Diversity liaisons and Procurement Professionals, too: "Purchasing People in Major Corporations"