Dear Martin
to translate a hierarchie use SE63, menu "Translation" ->ABAP Objects -> Short texts
Pop UP "Object Type Selection", S1-> SHI5 Extension of a Hierarchie,
double click and fill in: the name of the Extension, languages -> Button "Edit"
If you don't work with SE63 before, please try an simple example just to test SE63)
With Best Regards
Michael
Transport! see OSS 302929