Maximum Transform length for Startix IV FFT IP

Hi, I used Altera FFT IP to design my project. The quartus version is 9.0 while IP version is V9.0 Build 132.

I tried to configure transform length to 32768 but I found maximum Transform length is 16384. I read the datasheet of the FFT IP and found the maximum Transform length could be 2^16=65536. Is there someting wrong with my setting? Or Should I update my quartus II and FFT IP to latest version to support this feature?

Thanks a lot!