Cubase Pro 9.5 and Mbox 2 Pro???

Hello everyone,
I got a problem with Mbox 2 Pro and Cubase Pro 9.5 on Windows 7.
While with the older version (7.5) I was able to set buffer size in the software, now I can’t and I can’t do it too from the control panel of the device in Windows (it’s set to 256 and I can’t change it in no way).
I tried to install ASIO4ALL but under 256 it makes no sound or just crackle, so I can use ASIO4ALL with higher buffer to mix but not for recording with low buffer sizes like 64 and neither 128.
How can I fix this situation? The problem is hard and I can’t see no solution.
Thank you