can't create kernel kernel project

I can't create a kernel project for my Nios II design. I think the problem has something to do with the memory device. Normally, when I create a kernel project, it fills in the sdram automatically. But not in my project. When I select it manually, the finish button stays unavailable.

The sdram section in the ptf file seems to be identical. The base address is 0x2000000. There are two chips with 32 bit width each. They are accessed in parallel with 64 bit width. The sdram works fine without an operation system.

Where could be the problem?