Connecting to Facebook via Proxy

Hi,

We have Facebook sign-in and connect/disconnect running fine but now need to deploy to a server that restricts access to facebook urls.

We planned to connect via a proxy but cannot use the System property "http.proxyHost" & "http.proxyPort" as this may affect other apps running on the box.

Is there any other way to configure Spring Social to specify the proxy host and port?

Thanks for any pointers!