Microsoft Age Of Empires III: Expansions compatibility for LAN multiplayer?

Hi there,

I have both Asian Dynasties and War Chiefs expansions, and I am trying to have a multiplayer session between a laptop running the War Chiefs expansion, and another one running the Asian Dynasties. All three vanilla, WarChiefs and AsianDynasties are installed on both laptops.

• The network should be OK, since I can play Age of Empires II and Age of Mythologies multiplayer between both laptops without problems.
• I have chosen Spanish and Portugese home cities (is choosing home cities of civilizations present in the vanilla version a requirement?)
• Both laptops are running Windows 7, and have their firewalls / antivirus deactivated

No laptop can see the games initiated by the other. When explicitly giving the IP address of the laptop hosting the game, "no game is found". Using Wireshark I checked that packets on UDP port 2299 are correctly sent from both sides (when laptop A hosts the game, laptop B sends the unicast UDP packets but gets no answer).

I already checked http://support.microsoft.com/kb/819836/en-us, I could not see any useful hint for my issue there.

Thanks a lot in advance!

Jose