Reverse Lookup Problem for cisco 2811 DNS Server

Hi All
I set my 2811 cisco router as a DNS Server and it can convert Name to IP Addr. (I can see all websites with name) but I don’t know how can set it for PTR record(ARPA) {Convert IP to Name} now my setting is:

ip dns server
ip dns primary salam.ir soa ns1.salam.ir webmaster@salam.ir 86400 3600 120 9600 86400

ip domain retry 3

ip host mail.salam.ir 195.146.32.42
ip host ns1.salam.ir 195.146.32.2
ip host ns2.salam.ir 195.146.32.3
ip host www.salam.ir 195.146.32.44
ip host salam.ir mx 10 mail.salam.ir
ip host salam.ir ns ns1.salam.ir
ip host salam.ir ns ns2.salam.ir
ip host webmail.salam.ir 195.146.32.42

ip name-server 195.146.32.2
ip name-server 195.146.32.3
How can set PTR in cisco router?
Thanks
Kamal