UMLR — InteractionUse can not reference a CollaborationUse (as shown in Figure 17.24)

The specification contains following diagram:

It shows how a CollaborationUse w1 can be used to bind the parts of a concrete Class E to roles in the generic Collaboration W. The InteractionUse in the sequence diagram of E is then shown as if it references w1.Q. This is not possible, since an InteractionUse can only reference another Interaction. In the case shown it might just be inferred, since there is only one CollaborationUse. However, it is possible to use the same Collaboration multiple times with different role bindings, and then it is necessary to define which one is happening.

Suggestion
This is a useful feature. I think the Metamodel should be enhanced. One possibility would be to allow InteractionUses to reference CollaborationUses.