Sparx EA using Sequence Diagrams to capture linkages to requirements for operations.

[David M]

I am having some difficulty in sparx EA with sequence diagrams.
Sequence diagrams in EA rely on the use of operations. An operation in
my context is the same as an action in an activity diagram. The
supporting message in the operation reflects a specific message in the
related action. Ideally i want to indicated that the operation is the
activity, that way i can show linkages to requirements. This will
enable me to be able to generate a report on a sequence diagram that
shows the relevant components in use, the associated functions
(activities) used by each component and the requirements associated to
each function.

Right now it appears to be a duplication of effort in that an
operation is the same as an activity but EA will not let you select an
activity.

I believe this is overcome if swimlane diagrams are used to
demonstrated functional threads, however the client requested a
preference for sequence diagrams.

Any advice?