BIND and LDAP support

[Kernel Panic]

Apologies if this is not the appropriate list but I can't seem to find
one pertaining to the installation and configuration of BIND. I posted
the following message on the FreeBSD forums a few weeks back but have
had no replies, so I thought I'd try here on the lists:

System: FreeBSD 8.2-RELEASE 64-bit

Hello, I'm going to attempt to install the latest BIND port
(dns/bind98) and have a couple of questions about the available
install options:

WITH_REPLACE_BASE=true

Does this delete the base BIND version and if so would I need to edit
src.conf to tell the compiler not to reinstall base BIND when I do a
buildworld cycle?

WITH_DLZ_LDAP=true

Does this actually enable LDAP backend support or is it something
else? The reason I ask is because there seems to be a separate port
for BIND LDAP support but it's for an older version of BIND
(dns/bind97-sdb)

Thanks for any assistance.