Creating VIJAVA ServiceInstance using VIM UserSessionService without using username,password again

Hi All

Currently I am working on the VWC plugin using Flex - Java Service. I am using VIJAVA for vsphere releated opertaion.

I have successfully got the userSession from current VWC UserSessionService. I can get username, sessioninfo, serverinfo from this object.

Now i want to create new ServiceInstance object in vijava WITHOUT entering user credentials again as mentioned below.

ServiceInstance si =newServiceInstance(new URL(  "_https://10.x.x.x/sdk"),"administrator@vsphere.local",  "Password",true);

I DONT WANT TO USE THE ABOVE AND I WANT TO USE THE BELOW OVERLOADING. Or somehow i need to create ServiceInstance using UserSessionService object.

   ServiceInstance si =newServiceInstance(url, sessionStr, ignoreCert) or something equivalent

Kindly helpe me. Thanks in advance.