Can you tell me what is the best practise for identifying service consumers? In our layered SOA architecture we have services being consumed by both applications and other services.

Ideally I would like to go down to the service operation level but I can only add application consumers and am unable to create a ‘consumed by’ association for an operation. This is fine if the consumer is an app but if the consumer is another service operation I am unable to make the association at the operation level.
Is the standard practise only to identify consumers and associations at the services level ?

-Andy