I attempted to do the same, and it worked for me. here's a copy of what my csv looked like:
[root@airwave tmp]# cat controller.csv
IP Address,SNMP Community String,Name,Type,Auth Password,SNMPv3 Auth Protocol,Privacy Password,SNMPv3 Privacy Protocol,SNMPv3 Username,Telnet Username,Telnet Password,Enable Password,SNMP Port
10.10.10.137,public,,,snmp3user,md5,snmp3user,aes,snmp3user,,,,
I did cheat a little by using excel to generate the csv to make sure I had enough comma's to make the data line up. I did try to type the data a few different ways and looks like it's case sensitive to using lowercase md5/aes which I'm filing a defect for.