Remove Virtual appliance from database

Hi, 

Acronis virual Appliances (3of them) were deleted from Vcenter and removed from disk (in vcenter console, not from AMS console).

Their name are AcronisESXAppliance-1, AcronisESXAppliance-2, and AcronisESXAppliance-3.

They still appear in AMS and are "grey" and cannot be deleted, as they cannot be found anymore in vcenter,because  they doesn't exist anymore.

So, Another set of Acronis virtual Appliancewere were deployed in the vcenter AcronisESXAppliance-4 AcronisESXAppliance-5 AcronisESXAppliance-6 to make backup.

I want to remove any reference to the 3 first AcronisESXAppliance 1 2 and 3.

How to completely remove them from AMS database?

thank you for your help.

Damien