Hello,
If you still want to use auto-nat, it is as follows:
******create the object*******
object network Real-IP
host 1.1.1.1
***** enter the object subcommand mode and add the nat rule********
object network Real-IP
nat (inside,dmz) static mapped-IP
After the static keyword, you can use an IP address, network object or the interface keyword.
Note: NAT for traffic between interfaces is no longer a requirement after version 8.3
Regards,
Felipe