UMLTP23 — Test configurations and test items

How do we handle that a test item is a part of a particular system? How can we point to a part property of a composite structure? Can we use dot notation to say my test item is not just the type OpticalSensor but the UAV.PayloadCage.OpticalSensor ?

Why does the UTP not specify InstanceSpecifications of test configurations?  Perhaps we handle this through the test log structure to have test log entries that are instances of test configurations.