Solved it!
I don't understand why (maybe you guys do understand? If so, I'd be grateful if you could explain me) but the game would not read my version of the md5translate.trs file because it was in the enUS directory.
I just created a new MPQ "Patch-4.MPQ", put my minimap files into it and placed this little guy with the standard data patches in the "Data" folder. Worked like a charm.