SDLTM language codes - ES-LA or ES-419 ?

Hello,

If I create SDLTM EN-GB to ES-Latin America Trados doesnt use alphabetical code as usual e.g ES-AR (Argentina), but uses number code ES-419.
So sometime when I need make some changes directly in exported TMX, I dont know the number codes for respektive sublanguage, so I need to create sample SDLTM, create one sample TU, then export to TMX and loook into what is the number code.
Where is the principle? From where Trados uses information, for the Windows registry?, regional settings?.
Is there any map to know all Language codes?
Thank you for explanation.

Jiri Proniuk