Sure, open the OE. Select File->New. You now have a blank terrain square. Now hit File->Tile Properties. Put a check in theses 3 boxes:
-Is terrain cell
-Display terrain under tile
-Map selected texture over whole tile
Now your properties are set and your terrain square will have lines dividing it up like a pizza into 8 slices. You MUST have at least one object in each of the slices and do NOT place an object on any of the dividing lines. When done, save it as a new nttXXXX.til file and place it in your texsrc folder in your terrain.
If you wish to see the defaults, open them in the OE. Go to File->Open->Editor->ahstandard->tertile->nttXXXX.til