The SDK itself is not exposed through the web services, although if it's on BO 4.x it might use the RESTful web services which don't require a separate runtime/development installation. The regular web services and non-web services SDKs require a set of java libraries to be installed on the development workstations and the application servers where the applications that use the SDK run.
If you want more information, you're best be would be to start a new thread here instead of responding to a thread that's over a year old.
-Dell
