Did you change the BLB file path?
datablock fxDTSBrickData (brick64xCubeData){ brickFile = "./64x Cube.blb"; category = "Baseplates"; subCategory = "Cube"; uiName = "64x Cube"; iconName = "Add-Ons/Brick_Large_Cubes/64x Cube";};
Did you actually change the brick file to point to your blb instead of the 64x cube?
Wasn't there some sort of size issues? like 32x32 is the max size of a custom brick that players can see?