Modifying Root Motion Extraction

Greetings folks here,
since UE4 does not offer any kind of control about which transform components of the root motion should be extracted i’d like to add the necessary option myself. Since i haven’t really done that kind of Engine Source Modification before i’d like to get some advice on how i should do such thing and where all the stuff is that i need to change for it to be exposed to the UI in place of the (too) simple “Enable Root Motion” option. I think i’ve already found the part where it does the extraction itself but it would still be a lot easier for me if someone here who has a bit more experience that me with this kind of Modification could point me in the right direction.

Thanks in advance for any helpful comments.