ZBrushCentral

multiple normal maps in maya

hello fellow zbrushers,
i want to add multiple normal maps from zbrush and put them in maya
i have extracted the normal maps from zbrush, and they are working fine alone by themselves, when i try to add them together using nodes in maya they dont work and the mesh renders as broken glass

my uvs are laid out in four different quadrants of the uv grid such as
u 0 v 0 ((in the topleft quadrant of maya))

u -1 v - 1

u 1 v -1

u-1 v 1

the extracted texture color files are working great, i added them together using the plus minus average node and its working great, it didnt work with the normal map
any ideas would be great
keep in mind i dont want to put them in one quadrant so my uvs would be in one space…
anyone reached a solution for this problem please share it

thanks
omar mansour

anyone tried to do a similar approach before?