Joyce,
Can you please follow these steps to add the jars to buildpath :
1) Create User Library for WebSphere Runtime. Go to: Window -> Preferences -> Java -> Build Path -> User Libraries, click on New and enter the name. Now click on Add Jars and add jars you need from WebSphere installation.
2) Go to project Buildpath > Libraries > Add Library > User library > select the user library created in step one and click Finish.
Please take a look at this FAQ for more information :
https://www.genuitec.com/forums/topic/configuring-websphere-runtime-for-a-project-in-me-10-x/
Let us know how it works for you.