Adding a bump map to the TerrainFourLayer shader

I've copied this script for a TerrainFourLayer shader: http://www.unifycommunity.com/wiki/index.php?title=TerrainFourLayer but I need an input channel for a bump/normal map, like the TerrainTwoLayerBumped shader: http://www.unifycommunity.com/wiki/index.php?title=TerrainTwoLayerBumped

I'm not a coder, but is there some script I can add to the Four Layer shader that will add a bump/normal map channel? I'm using Unity 2.6

im not quite sure what you mean but there is a script for adding bumpmaps to terrains:

here