Reference set:query

Hi All,

I have created a dummy model to understand reference set. Here I have a problem regarding selecting the reference set

1. The NX default has EMPTY, Model and Entire Body

2. I have created one more set called SHEET with surfaces in it

3. When I switch to SHEET ref. set, it will hide all other things except the surfaces(Whatever the surfaces I chose will        shows up)

4. I go back to Model ref.set and hide everyting except the solid.

5. Now if I choose SHEET ref.set, the sheet will disappear!!!!!!

I need those surfaces when I replace reference set with SHEET. How can I choose reference set then??