Quoting Quanah Gibson-Mount <quanah@zimbra.com>:
I do it via ldapmodify: dn: olcOverlay=syncprov,olcDatabase={3}hdb,cn=config changetype: add objectClass: olcOverlayConfig objectClass: olcSyncProvConfig olcOverlay: syncprov olcSpCheckpoint: 20 10 olcSpSessionlog: 500
Thanks, Quanah. Just a bit more Googling and I figured this one out myself, but these configuration attributes are not well documented yet, at least not for cn=config. They're not yet included in the slapo-syncprov man page and (correct me if I'm wrong) the online documentation doesn't seem to mention them either.
Cheers, Jaap