How to stop auto feature simulation xpress

Hi,
I'm trying to do an FEA on some models as part of my degree course work, I dont have much experience with FEA, or really SW, but need it as part of the analysis.

I keep having a problem when trying to set fixtures that when I select a part the internal patterned parts (the more vertical members) disappear.

Basically what I am doing is creating a steel reinforced concrete structure with different orientations of steel reinforcement to see how the forces will react in comparison to each other.

Is there any advice anyone can give me?
Is there anything I have to do in particular with setting up the composite structure properly?
Do I have to create the steel reinforcement and concrete sections as different models to get the different material properties and then join them using assembly?

the model is the kind of thing I'm trying to do FEA on