I have used eLink Adapter to communicate to the Vantive system. I have not yet heard about the eLink adapter for clarify. So, you may need to develop it yourself and that is where the Adapter Development Kit comes into picture. In order to develop your own adapters, you need to be familiar with Jolt APIs (written in Java) and FML also along with ADK. The Jolt APIs are used to communicate with eLink through the FML fields from the Java code.
You can follow the steps mentioned below:
1) Develop the adapter using ADK and FML.
2) Deploy the adapter in the eLink platform.
3) Access the eLink services (provided during deployment) using Jolt APIs.
You can get detailed information on these topics from http://edocs.bea.com