Because replica IDs repeatedly occur in the metadata for a replica and are suggested to be 16-byte GUIDs, Sync Framework represents replica IDs by using a map between replica IDs to 4-byte replica keys. Sync Framework then uses replica keys where references to particular replicas are required.
To obtain a new IReplicaKeyMap object, first create an IProviderSyncServices object by passing CLSID_SyncServices and IID_IProviderSyncServices to the CoCreateInstance function. Then, create an IReplicaKeyMap object by calling IProviderSyncServices::CreateReplicaKeyMap.