You must change the Src/LS-Adapter/So6-Adapter/resources/security/keystore certificate before compiling. You need it signed by an authority valid for java webstart.
Build your own certificate with keytool in the jre or another x509 tool. Get an authority sign it. Replace the distribution certificate. Re-build. Re-deploy. And your done. I don't know if java web start is updating its authority certificate or if it own any by default, check and add the authority certificate if needed.