However it did take me about 2 days to do, so because there seems to be a lack of information about it on the internet I'm going to give steps on how to get the trigger keys to work on a xbox360 controller.
First of all you need to have Micrsoft Visual Studio 2010 installed. This can be rather tricky to do because now microsofts website only supports bewteen 2015 and 2012 but heres a download link to MSCS 2010 ultimate. (All though this installation seems like it can take between 3-4 hours.)
Download Cnet: Microsoft Visual Studio Ultimate 2010
Secondly you will need to have MSVC 2010 SP1 Runtime Installed, this one is a bit easier to find on microsofts main website for whatever reason, it shouldnt take as long, but it would probably install in less then a hour.
Microsoft Visual Studio Service pack 1
Next, you will want to go here to download XCBD,
XBCD 0.2.7 Release
Then click on the top link where it says My SkyDrive or Mediafire, Then click Skip Ad on the top right corner (it loads after 6 seconds or so), then you should see the three links to the files on the screen I just downloaded the XCBD zipped file. Also make sure when you install XCBD that you right click it and run it as a administrator as it need to change registry values just to reference his post:
SquallLeonheart said:
On Vista/Windows 7 with UAC enabled, you must run the Setup Utility in this same manner (Run as Admin) for it to be able to read and write values to the registry.
Lastly after you install XCBD completely, you do a search for XBCD Setup Utility or just "Setup Utility," to configure it, for some reason it installs into the system32 directory and I cant figure it out how to find it manually.
Youtube XBCD instruction video
So once you open the software, make sure you have your Z, Rz, and your Slider Axis off (unchecked box), I would also set it to a number of 12 buttons (near the on the bottom), and click save.
and thats pretty much it, FFXI should work with the controllers trigger keys. You can calibrate it under Control Panel=>Device&printers=>Right Click Controller Icon=> Game Controller Settings,
but I don't think you really need to.. I hope someone finds this useful.