It seems that no matter what you select here, if the port is
389, it does STARTTLS:
Jan 29 17:59:16 seaknight slapd[840]: conn=0 fd=15 ACCEPT from
IP=127.0.0.1:53243 (IP=0.0.0.0:389)
Jan 29 17:59:16 seaknight slapd[840]: conn=0 op=0 STARTTLS
Jan 29 17:59:16 seaknight slapd[840]: conn=0 op=0 RESULT oid=
err=0 text= Jan 29 17:59:16 seaknight slapd[840]: conn=0
fd=15 TLS established tls_ssf=256 ssf=256
This is encouraging - I guess you are not using the same version of
slapd as I am? (I'm using 2.4.7, which apparently has a bug with
STARTTLS, at least in Debian it does).