I've done an app which uses C2DM pusn notifications. Everything works fine as long as I am connected to the GSM/3G network but when I switch to WiFi it does not always work and I do not receive push notifications.

I understand the technical problems when it comes to WiFi and push (firewalls et c). 

My question is if there's any smart solutions for this (Yes I know I could switch to "polling" in my app). Is it possible to use GSM/3G and WiFi at the same time, or is Android already doing this when connecting to WiFi? 

/ Henrik