Last year I held a talk about using a metamodel to communicate your service oriented architecture (SOA) on an IT conference in Stuttgart. I had the idea to model what we understand as our SOA effort as a metamodel when reading the great book domain driven design by Eric Evans. When talking with people in the company about our view on how we wanted to implement SOA it was quite difficult to explain. The model helped us to communicate to people outside of the project as well as it helped us to establish a common language inside the team.
While the effort of creating a metamodel is quite substantial I can only recommend to other projects doing SOA to try the same. You can use the model we created as a starting point as it is quite general.
You can find the presentation EnBW SOA Metamodel here.