Looking for help with TGEA in the Shader Engine

With the Torque Game Engine Advanced in the Shader Engine in the Terrain Editor how do you first make the area that you are working in (Geoterrain mode, the area where the terrain editor brush turns red, when set on hard brush) bigger so as to be able to create larger playable areas, with out increasing the block sizes?

And also how do you keep it from mirroring in the nonbuildable area (the area where the terrain editor brush turns blue)?

I have gone through and read all of your tutorial for both the Torque Engine and the Advanced Engine and I have searched and read the forums multiple times with little to no help.

Any help will be much appreciated.