problem with nios2 cypress sram controller

I'm using a cyclone 3 and a cypress Sram cy7c1380d.

This sram has a 512kB * 36 dimension, but in the sopc builder, the sram controller dosen't support this dimension(only 1M*18, 2M and 4M are supported).

i tried to use the 1M*18 controller, it requires 20 pins assignment for the address, but my own sram has only 19 pins for address. And the failure of a helloworld test with nios ide turns out that a controller of 512kB*36 dimension (which has only 19 pins for address) is necessary.

Have you guys ever met this problem?

can anyone help me with this? it drives me crazy!! :(

ps: using quartus 10.0 and sopc builder 10.0