Firstly - it doesn't look like Active Directory Authentication is supported (only community or USM is available) - some interesting reading on USM in RFC 3414 http://www.rfc-base.org/txt/rfc-3414.txt
CLUSTER01::> security login create -username domain\svc_monitoring -application snmp -authmethod domain -role readonly -vserver CLUSTER01 -comment "SNMP User for monitoring"
Error: snmp: cannot use domain to authenticate
So a local user needs to be created.
CLUSTER01::> security login create -username svc_monitoring -application snmp -authmethod usm -role readonly -vserver CLUSTER01 -comment "SNMP User for monitoring"
Enter the authoritative entity's EngineID [local EngineID]:
Which authentication protocol do you want to choose (none, md5, sha) [none]: md5
Enter the authentication protocol password (minimum 8 characters long):
Enter the authentication protocol password again:
Which privacy protocol do you want to choose (none, des) [none]:
This should be all that is required from the NetApp end, then you can run through and configure your filer