Detecting vCloudClient timed out session and extending

I am using the VCD 5.1 SDK for .NET, and am running into an issue where I get "Access Denied" errors when the vCloudClient session expires.

I have a static vCloudClient object (com.vmware.vcloud.sdk.vCloudClient) that is used every time a user makes a request to the application that requires vCloud interaction. After a while, though (30 mins?), the session expires and the client starts returning back "Access Denied" errors.

So if I want to detect that the vCloudClient has expired, how can I do that? Looking at the object, I'm seeing methods like ExtendSession(), SetConnectionTimeout(), and SetSocketTimeout(). A post here:http://communities.vmware.com/message/2137166 says that ExtendSession() will return true if the connection is alive when it's called and false otherwise, leading me to believe that it can't be used is the session has already expired.

How can I detect that the session has expired and extend it?

Thanks.