the easy way would be to use a matrix editor that allows you to paint textures
otherwise you need and image with both your textures on it, use the prepare matrix textures into 2 sections and then find the matrix coordinates that you wan to texture and use
set matrix tile matnum,x,z,2
in which matnum is the matrix number
x and z are a number between 0 and 49(for your matrix)
and 2 is the texture tile number eg the second texture on your matriux image.
You know whats weird???
Donald duck never wore pants, yet everything time he got out of the shower he put a towel around his waist...
Whats with that???