Hi,
I don’t know if there is anything I can do from the plugins perspective. If the plugin works via a regular request, then it is up to the proxy to serve the content properly. The problem with web proxies is, that they usually temper with the content served, causing issues – such as replacing URLs, replacing certain script parts.
I am not sure if there is anything to do about this, except maybe I would rather suggest using a VPN instead of a proxy – that will not temper the information sent to the destination browser.