From what i read in the manual doing the static IP bit is actually somewhat simple. Go into Expert Mode and click on Configure. In the list of things to do click "Static IP ARP" (just below Static Routes near the top). Now, you make up an Ip address for the router to use just for the PS3 (just change the last numbers to a bit higher than the router's IP, maybe use 10- the first 3 segments remain the same) and enter in the MAC Address in the blanks beside it and hit Submit.
The DMZ is called "Exposed Addresses" on the Netopia- this could help as this would place the PS3 outside the firewall protection. You would still need to make a custom IP address for the PS3 to do this, however. You'll find this under Security. Once you make up the IP address go in there and put the same IP address in the Start and End IP Address blanks as well as all the ports in the range shown. Click the Submit button when done.