Have you ever needed to not NAT across from the inside interface to the DMZ interface of the ASA? Seems like when you traverse from one interface to another, you are going to have to either NAT that traffic or not NAT it. Either way, you are going to have to tell it to do something. Here is what I did when I wanted to go from the inside interface to the DMZ interface.
access-list 107 extended permit ip 192.168.17.0 255.255.255.0 192.168.9.0 255.255.255.0
nat (inside) 0 access-list 107