UMLR — should be able to show gates on communication diagrams

In the 2.1.1 specification (070205):

Although the superstructure specification does not mention it, I believe that we should be able to show gates on communication diagrams.
Gates are not connectable elements so we cannot attach connectors to them. How then would we show message pathways (connectors) to the represented lifeline on the communication diagram? Gates don't "represent" connectable elements as lifelines do.

I would like to request clarification on this point.