Revit :: Create A Custom Floor Tile

I'm trying to create a custom floor tile but having issues doing it.  1st I create a generic 12' create floor, then use that floor to create a subfloor to try to create a tiled floor that is offset 1/4" from the initial floor.  I select the floor, click edit material, select ceramic tile,.. get to the graphics property, select surface pattern and select 12" tile, click done, then OK but ... nothing happens.  
 
I would also like to customize a pattern.  I would like to create a patter that uses a 12"X12" tile with (2) 5 7/8"X5 7/8" tiles.
 
I tried to use the *.PAT technique but finding it difficult to do what I want so I found the hatch22 but still find that rather difficult.