if you have it working just untick DHCP in LAN settings and it will become static on that i.p
or if you have lots of things on your network change the last two digits of the top line in LAN to a higher number, so you won't get conflicts,
e.g mine is
if you want to be even more sure not to get conflicts go into your router and change DHCP range to be below your TM i.p.
also you shouldn't need any password or anything if your connecting over wired lan direct to router...