UPDATE:
Finally after long wait and interactions with IBM support I got it resolved:
- No problems with IBM JRE
- For Sun/Oracle JRE it requires extra configuration for ORB e.g.
jndiProperties.put("java.naming.corba.orb", com.ibm.CORBA.iiop.ORB.init((String[])null, orbProperties));
and orb.properties from WAS or AppClient JRE is required to be provided as "orbProperties"