5.1 broke the motion detection with ACC you need the new build of 5.1 140217
Its on their site:
FTP site below under folder /VMS_Firmware/ONVIF.
ftp://ftp.hikvisionusa.com
Username: hikfirmware
Password: Hikvision123
You will have to TFTP if using china model.
I have 2 2032's a 2632 and a 2632 on Avigilon with motion.
I tried everything before I found out there was an Onvif issue with the first 5.1 build.
Here's a pic of the newest ACC