The provider registration approach - registering one provider per subclass (Xen_<classname>Provider, KVM_<classname>Provider) caused interoperability issues with Pegasus and sfcb. The same call returned duplicates with sfcb and worked with Pegasus. Diff to patch #1: - clarified patch message - added match_hypervsior_prefix to association's handler functions Tested for sfcb and Pegasus, but encountered a strange behavior with Pegasus. Please can someone try to reproduce this on his/her system ? The following call wbemain -ac CIM_HostedDependency -noverify 'http://pegasus:pegasus@localhost/root/virt:KVM_HostSystem.CreationClassName="KVM_HostSystem",Name="localhost.localdomain"' should return localhost:5988/root/virt:KVM_ResourcePoolConfigurationService.SystemCreationClassName="KVM_HostSystem",SystemName="localhost.localdomain",CreationClassName="KVM_ResourcePoolConfigurationService",Name="RPCS" localhost:5988/root/virt:KVM_VirtualSystemManagementService.SystemCreationClassName="KVM_HostSystem",SystemName="localhost.localdomain",CreationClassName="KVM_VirtualSystemManagementService",Name="Management Service" localhost:5988/root/virt:KVM_ComputerSystem.CreationClassName="KVM_ComputerSystem",Name="qemu1" but the returned results for Pegasus depend on the order, in which the providers Virt_HostedDependency and Virt_HostedService have been called. Either localhost:5988/root/virt:KVM_ResourcePoolConfigurationService.SystemCreationClassName="KVM_HostSystem",SystemName="localhost.localdomain",CreationClassName="KVM_ResourcePoolConfigurationService",Name="RPCS" localhost:5988/root/virt:KVM_VirtualSystemManagementService.SystemCreationClassName="KVM_HostSystem",SystemName="localhost.localdomain",CreationClassName="KVM_VirtualSystemManagementService",Name="Management Service" is returned if, Virt_HostedService was called first or localhost:5988/root/virt:KVM_ComputerSystem.CreationClassName="KVM_ComputerSystem",Name="qemu1" is returned, if Virt_HostedDependency was called first. Thanks ... Heidi