I know, this entry is quite old, but others might still be interested.
I've came up with another (admittedly unconventional) solution that doesn't require owners of the German version to buy an additional English one from GoG, or to ask other users in this forum to provide their English version of sparky_fs2.vp:
The
Blue Planet Mod seems to contain a different version of the font used for HUD texts (at least compared to the German version). I found a direct download link
here, however it should also be possible to extract the font file from the relevant VP file of Blue Planet (haven't checked which one yet).
If that file is copied into \data\fonts of the FreeSpace2 root directory (usually C:\Games\FreeSpace2), it obviously overrides the original font located in sparky_fs2.vp during game runtime. That way, both the annoying "ü" weapon selector as well as the missing digits (e.g. in distance or health values) seem to be gone.
I did however no extensive testing, so maybe this solution comes along with other flaws (such as erroneous texts or other broken mods).
I also know that this is not what BP (very great mod(s), my sincere compliment to all contributors) is made for. Yet, since the font file is located in a public SVN, I assume it is "more legal" to use than copying it from the English version of the retail game without actually owning it.