Airport Channel 12+

Can one of you tell me how to enable Airport to use channel 12 and 13 on a MBP from the US?

My WLAN operates on channel 12 at home (which is perfectly fine in my country). I'd switch to a different channel if it wasn't for all the other WLANs in the proximity.
There is no option in the preferences menu, but it should be possible to switch this behavior in software. It's not like they build different sets of Airport cards in China...

I'm sure someone has asked this before, but I couldn't find anything.

Update: After swapping drives with my EU MB (sad story) channel 12 still isn't accessible.

So it should be firmware related. The question is: How do I get a non-US firmware for my airport card?

That's what I'm currently doing, but channel 12 provides the best range for me*, because lots of other networks are on channel 1-11 (most on channel 6, which seems to be the default on many models*).

I've got a very powerful router and our apartment isn't that huge, but one of our laptops has a very weak reception (12" PB) and it only works on channel 12 in one of the rooms.


*In theory the best signal can be archived on channel 6, because that's exactly the frequency the antennas are designed for. However, it's advisable to set the channel to 1, 7 or 13, because those are the only frequencies which don't overlap. In practice it doesn't help much because most users are not aware of it and simply choose a number they like or use the default channel. If it was easy, I would ignore regulation and set the router to 14.
Hope I'm not boring anyone with this rant 😀


edit: Some update must have fixed this:

noname:~ robert$ sudo dmesg | grep en1
Password:
e-en1: interface en is going DOWN
...
en1: 802.11d country code set to 'DE'.
en1: Supported channels 1 2 3 4 5 6 7 8 9 10 11 12 13 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140
AirPort: Link Up on en1

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