opmanager 10 issue in esx datastore discovery

Hi everyone,
I'm encountering a strange issue in opmanager 10.
Here's my infrastructure: I have 2 groups of esx hosts, each group is composed by 8 hosts (total 16 hosts).
Every host of a group can see all the available datastores, but only a subset is mounted on each host (by vsphere client I'm able to see all the datastore, but most of them are correctly marked as unmounted).
The issue is that when I discover the esx host by using opmanager, in the snapshot page of the host I can see all the datastores, and the unmounted ones are alarmed as completely full. This is obvious because the size of the unmounted datastores is always reported as 0! 0gb free of 0gb --> critical alarm.
Is it possible to delete the unmounted datastores in order to be able to monitor only the correct ones, and avoid the receiving of tons of useless alarms?
thanks and regards