You'll have to convert the dds from SC2 to TGA's. The "dds" used by NWN is not the same, and yours won't work =)
About linking and such, take a look at this video
http://nwvault.ign.c...s.Detail&id=184
Its way outdated now, but still has the linking part and such right.
To export, instead of doing what is shown in the video, just select the base, and in the right panel choose "export".