Developers must develop and deploy their web services along with OpenSSO Enterprise.
If web services already exist in the environment, the developers must integrate them with OpenSSO Enterprise.
OpenSSO Enterprise ID-WSF framework is tested in interoperable environments and certified by the Liberty Alliance. So the web services are almost certain to work in multi-vendor environments as long as the remote party is also a certified implementation.
The lack of mobile client support with the OpenSSO Enterprise Client SDK may be a limitation. However, the primary use for OpenSSO Enterprise is in enterprise web service deployments.