System audio enabled Airplay speakers, only one of two shows in list

So I recently discovered the feature to enable Airplay for all audio on your Mac instead of just through iTunes. Really happy about this I wanted to try it out right away.

But opt-clicking the volyme control icon I discover only one of my two airplay speaker setups is avilable in the drop down list, and when I try clickin a couple of times the device available in the list alternates between the two. Wierd! And whats wierder is my friend sitting next to me with his MBP has no problem, and gets them both in his list, and we have just about the same computer setup.

I'm running Mountain Lion on a early 2009 MBP, with a new Airport Express as my main wireless router with airplay speakers connected, and a second older Airport Express as an wifi extension with airplay speakers in another room.

Any help with this would be much appreciated!

Thanks!

/jeppe