SSLHandshake exception while using vsphere sdk on vcenter 5.5

Hello

I am attempting to register an extension with vCenter server 5.5. In doing so I am starting to see SSL Handshake exception (com.sun.xml.internal.ws.client.ClientTransportException: HTTP transport error: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake).

I have called appropriate method to trust all certificates etc. The same code works when I try to register the same extension on vCenter 5.1.

Appreciate any pointers..

Thanks

liz