Custom Monintor is changing the specified OID

I am seeing a probelm in OpManager 6.0 when adding a custom monitor for my Dell PowerEdge server. The probelm is when I create a custom monitor using the OID obtained from MIB Browser, OpManager is appending a ".0" to the OID.

e.g I am creating a custom monitor "ifOperStatus.65540" to view the operational status of my GigE interface on the poweredge. After adding the custom monitor when I test using "Test Monitor" I get an error "The Monitor did not respond to the test request". When I look at the OID, I see OpManager has appended a ".0" and it now reads "ifOperStatus.65540.0" which the cause of the problem.

In order to verify this I tested both OIDs in MIB browser and the one with the ".0" appended also fails in MIB browser as follows:

MIB Browser output for OID "ifOperStatus.65540":
ifOperStatus.65540:up(1)

MIB Browser output for OID "ifOperStatus.65540.0":
Output for "ifOperStatus.65540.0":
Request failed or timed out. Response PDU received from 192.168.1.34
Error Indication in response:
There is no such variable name in this mib.
Errindex: 1

I have noticed similar probelm with Cisco, Lucent and other devices where Custom Montor is appending 1, 2 or even 3 0s to the specified OID.

How do I work around this probelm and have custom monitor not alter the OIDs that I specify?

Thanks