Reverse DNS on a /27 delegation and zone files

[Alex]

Hi,

I'm using bind v9.4.2 and v9.6 on Linux. My service provider has given
me a /27 fro their block for reverse delegation of DNS. I believe I
have it set up correctly, and all IP resolution works, but AOL and
Cox, for example, think it's wrong and mail is bouncing:

A22F3560271    69461 Sun Mar 28 01:53:13  alex at smtp01.example.com
(host mailin-04.mx.aol.com[205.188.146.194] said: 421 4.2.1  MSG=:
(DNS:NR)  http://postmaster.info.aol.com/errors/421dnsnr.html  (in
reply to end of DATA command))

Resolving the nameserver responsible for that range returns this:

$ nslookup 64.3.yy.3

Server:         127.0.0.1
Address:        127.0.0.1#53

Non-authoritative answer:
3.yy.3.64.in-addr.arpa  canonical name = 3.0/27.yy.3.64.in-addr.arpa.
3.0/27.yy.3.64.in-addr.arpa     name = smtp01.example.com.

Authoritative answers can be found from:
0/27.yy.3.64.in-addr.arpa       nameserver = ns.example.com.
0/27.yy.3.64.in-addr.arpa       nameserver = ns1.example.com.
ns.example.com  internet address = 64.3.yy.3

Do I also need to provide PTR records for these name servers? If so,
how can I modify my reverse zone file to include that information? My
named.conf has the following describing the zone:

zone "0/27.yy.3.64.in-addr.arpa" {

The zone file itself has the regular reverse-zone syntax with this
ORIGIN statement:

$ORIGIN 0/27.yy.3.64.in-addr.arpa.

On a somewhat-related note, does bind-v9.4.2 support the '-' zone
syntax notation? I was getting "bad data (check-names)" (from memory)
when using the hypen, and learned the hard way I had to switch to the
slash. Where is this change documented?

Does anyone know if this format is documented well in O'Reilly's
DNS&BIND v5? Do you know up to what specific version it's applicable,
or perhaps even it's current?

Thanks,
Alex