SSL Connection between Glassfish and WSO2. How to install certificates?

SSL Connection between Glassfish and WSO2. How to install certificates?

I try to connect a application running on a glassfish server with an wso2
application (WSO2 ESB). My Problem is, that I can't get a connection
because I have problems with the certificates.
I'm really new to SSL, so a step by step instrutction would be very nice.
Error on WSO2 ESB Console:
[2013-08-26 11:28:10,659] ERROR - SourceHandler I/O error: Received fatal
alert: certificate_unknown
javax.net.ssl.SSLException: Received fatal alert: certificate_unknown
at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1619)
at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1587)
at sun.security.ssl.SSLEngineImpl.recvAlert(SSLEngineImpl.java:1756)
at sun.security.ssl.SSLEngineImpl.readRecord(SSLEngineImpl.java:1060)
at
sun.security.ssl.SSLEngineImpl.readNetRecord(SSLEngineImpl.java:884)
at sun.security.ssl.SSLEngineImpl.unwrap(SSLEngineImpl.java:758)
at javax.net.ssl.SSLEngine.unwrap(SSLEngine.java:624)
at
org.apache.http.impl.nio.reactor.SSLIOSession.doHandshake(SSLIOSession.java:163)
at
org.apache.http.impl.nio.reactor.SSLIOSession.isAppInputReady(SSLIOSession.java:273)
at
org.apache.http.impl.nio.SSLServerIOEventDispatch.inputReady(SSLServerIOEventDispatch.java:229)
at
org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:158)
at
org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:340)
at
org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:318)
at
org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:278)
at
org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
at
org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:54
2)
at java.lang.Thread.run(Thread.java:722)