For everyone who is interested. Here a small tutorial how to decompile most of the .luac files:
1. Get luadec 5.1
2. Extract it to a folder.
3. Extract from the .smod the .luac you want to decompile.
4. Open up your cmd and browse to the folder where you extracted luadec 5.1
5. To decompile enter something like this into your cmd:
6. After hitting enter the console outputs the decompiled content (marked red in my image):
7. Just copy the output to your favorite texteditor (mine is notped++) and save it as orginal_filename.luac
8. Exchange your created .luac with the original in the stonehearth.smod
Hope this helps someone. When i have forgotten something just reply to this post 
Happy Modding everyone! 