Using a Specification as a Service Signature
You can use a specification as the service signature. A specification is a “free-standing” IS element that defines a set of service inputs and outputs.
Keep the following points in mind when using a specification to define the service signature:
A specification wholly defines the input and output parameters for a service that references it. This means that you cannot directly alter the service’s input and output parameters through the service Input/Output tab. (
Designer displays the parameters, but does not allow you to change them.) To make changes to the input and output parameters of the service, you must modify the specification (which affects all services that reference it) or detach the specification so you can manually define the parameters on the service’s Input/Output tab.
Any change that you make to the specification is automatically propagated to
all services that reference that specification.
If the specification resides in a different package than the service, you must set up a package dependency. For more information about package dependencies, see
About Package Dependencies.
To assign a specification to a service
1. In the Package Navigator view, open the service to which you want to assign a specification.
2. Click the Input/Output tab.
3. In the Specification Reference field, type the fully qualified name of the specification, or click 
to select it from a list. 4. Click OK.