Hi Adrian,
If I am understanding your question correctly then you want to do a static NAT from one subnet to another. Please correct me if I am wrong.
If you are doing the NAT of complete /24 subnet to another using the static NAT you need to have 255 IP address.
For Example :
object network obj-10.1.1.0
subnet 10.1.1.0 255.255.255.0
nat (inside,outside) static 2.2.2.0
Here 2.2.2.0/24 NAT's to 10.1.1.0/24 subnet
You can refer the below document for the pre and post 8.3 NAT configuration
https://supportforums.cisco.com/document/33921/asa-pre-83-83-nat-configuration-examples
P.S. Please rate helpful posts.
Thanks,
Shivapramod M