Ansys workbench modelling problem

Hi

I'm a mechanical engineering working on modelling composite in ansys workbench. I have a problem in modelling a composite plate with ACP. To do this, i created a static structural and modeled a surface body of a plate and after applying loads and boundaries, i attached to it an ACP(Pre). The procedures has been done like Tutorial 1 of ACP of ansys workbench 15.

The question is that what is the relation between surface body thickness and total thickness of composite plate modeled in ACP by defining layers? Do they must be equal or surface body's thickness isn't important?

Another problem is that, after the solution is done there is a warning that says surface body's thickness type must be on "middle" for "imported layered section" but the surface body doesn't seen in the middle of the layeres modeled in ACP! how could i define the layers in ACP so that the surface body is in it's middle?

i'm in a hurry

Thank you alot