olcAuthIDRewrite

[Willie Gillespie <wgillespie@es2eng.com>]

Using OpenLDAP 2.4.18:
Anytime I try to put something/anything in the attribute 
olcAuthIDRewrite for dn: cn=config I get:

conn=1 op=8 MOD dn="cn=config"
conn=1 op=8 MOD attr=olcAuthIDRewrite
conn=1 op=8 RESULT tag=103 err=80 text=<olcAuthIDRewrite> handler exited 
with 1

Am I putting in the wrong data?  I've tried all sorts of combinations, 
even simply:
{0}authid-rewriteEngine "on"

I can't seem to find much documentation on the whole thing either.

Thanks for any pointers.

Willie