Java APIs

Hi -

I have gone through a few threads regarding issues with RMI callbacks and firewalls etc. I have a peculiar problem whereby I need to make a RMI callback but that can only happen over a socket initiated by the client.
A little bit more about my problem. I am connecting the client via VPN and the VPN software we are using is CheckPoint which uses IPSec as the underlying tunneling protocol. I am not an expert on VPN, but the problem we have is that the client machine (outside the network and connected via VPN) retains its local IP address. So, when the server wants to make the callback, it is unsuccessful since the IP address of the client is meaningless at the server side.
To add to my woes, the client RMI invocation and the callback is happening in a 3rd party API we are using. So, I have no control over the actual RMI call being made.

My analysis shows that if somehow I can route the callback over the socket on which the initial RMI call was made (or for that matter any socket which the client has initiated), then I will be able to successfully manage the callback. All I have to play with is the RMISocketFactory and I somehow need to manipulate the RMISocketFactory on the server side into sending the callback over the initial socket. If anyone out there knows how this can be done, I would greatly appreciate their help.

Thanks,
Rubal.