Hey Roberto, I've got it working just fine.
I assume your phone can find both the Tradfri and Flic hub?
You might want to check if both hubs are on the same network (especially if you use them over WiFi and have more than one Access Point).
I've actually connected both hubs over ethernet to the same access point (just worked out that way) but you might want to try over cable in case the above doesn't help...
Good luck!
Joey