Changing Flex material in Allegro PCB Designer 17.2

Hi,

I am using Allegro PCB Designer 17.2 and i'm designing a Rigid flex board. There are few problems which i am facing in this design.

1. After adding the multiple stackup say Flex1 and Flex2 along with primary. If i change the layer material of layer 2 in Flex1 ,the same material will be selected the primary stackup as well. I want to use two different material in flex and  primary stackup. How can this be done?

2. The number of layers in Flex1 should be 2 and the number of layers in Flex2 should be 4. How can this be done?

Help me on this issue.

Regards,

Chadga