NNMi API - SNMP query using a community string with indexing for VLAN MIB

I'm trying to obtain the dot1dTpFdbPort MIB for a specific VLAN. In order to do it I need to poll the device using <community@vlan_id> has the community. 

I've tried to do this using snmpwalk and It worked, but when I try to do it using the NNMi API and by changing the v2ReadCommunityString field to <community@vlan_id> it doesn't...

The response from the API call doesn't contain any value associated with an OID and the community string that NNM says it used is just the community without the VLAN indexing.