Socket.io with PhoneGap disconnects when application is in the background

I have a phonegap app (currently on Adroid only) that uses socket.io against a node.js server. Everything works fine when the application is in foreground. The problem is that when it goes to background, after 3-4 minutes I see a disconnect on the server. This happens even if from the client I send emit() while the app is in background.

I have tried all socket.io options, e.g. keepalive, timeout, etc., but nothing helped so far.

Anyone with similar problem and possible solution?

Thanks in advance!