[sentinix-list] Using Cacti with SNMP indexed

Hi all,

I'm not an SNMP expert, but I would like to monitor the switches on my
network. 

1) I have tried to to a "snmpwalk" on the Sentinix box and I get a lot of
counters and everything from the switches, so there is contact.
2) When I try to add a SNMP counter I do it with the
Generic-SNMP-enabled-host and in the data source window I get a "Get SNMP
Data (Indexed)" entry when I wan't to get the interface traffic for example.

The question is how do I fill out the "Custom Data [data input: Get SNMP
Data (Indexed)]", there are 3 values and I can't find any documentation at
all:
Index Type
Index Value
Output Type ID

What does the values mean and how do I monitor the traffic of some SNMP
enabled switch ?
best regard 
Niels