Setting up a sub-domain on BIND 9

[Gary Clemans-Gibbon]

I'm trying to set up a sub-domain on BIND 9 on OpenBSD.

I've tried a CNAME record but it didn't work.

Currently my zone file looks like this (details obscured).
Please can someone show me what to add to be able to have
mysubdomain.mydomain.com work. Many thanks in advance,

Gary

# cat 
db.mydomain.com                                                                        

$TTL 900
@       IN      SOA     mydomain.com. root.mydomain.com. (
                        2005050102      ; serial
                        1h                      ; refresh -- 1 hours
                        1h                     ; retry -- 1 hours
                        2592000          ; expire -- 30 days
                        345600  )         ; minimum -- 4 days
                IN      NS      ns1.mydns.com.
                IN      NS      ns2.mydns.com.
ns1             IN      A       xx.xxx.xxx.xxx
ns2             IN      A       xx.xxx.xxx.xxx
@                       A       xx.xxx.xxx.xxx  ; makes 
http://littlebeargolf.com work
www                     A       xx.xxx.xxx.xxx  ; makes 
http://www.littlebeargolf.com work              
mail                    A       xx.xxx.xxx.xxx  ; makes it find the mail 
server