UMLR — Section: 15.3.7 Constraint [2]

Constraint [2] says: A protocol transition never has associated actions. My problem is that this constraint makes it impossible to specify a consistent pair of a server protocol state machine (PSM) and a client PSM. The server PSM has call events as triggers. It also has internal events causing autonomous state transitions. However, the latter transitions must be notified to the client PSM. This can only be done by actions in which signal events are generated to the client FSM. Such signals are the triggers in the client FSM; and in fact the same problem happens here. Since the call events to the server PSM are caused by internal events at the client PSM, that force call events to the server PSM in the actions. I hope this issue can be solved or at least clarified. Thanks.