Setting CAS Parts through "loot_actions"

Does anyone know how, if possible, one could force a particular CAS part by using a trait (and subsequent buffs etc.). So far I've been able to use the appearance_modifier as a part of the buff itself, to force the particular CAS part while in game, but it doesn't actually seem to change what CAS parts the Sim is really using. It would be a much more elegant solution if I could simply force the CAS Part onto the Sim, since the appearance modifier is not displayed while in CAS, the reason being that the CAS part in question changes quite a lot, and to really have any control of the appearance of the Sim right now, I have to put on a functional duplicate of the CAS part while editing in CAS.

Any help would be greatly appreciated, also if someone has seen any mods that appear to do this. I do admit my skills in XML are fairly lacking, but just looking what other people have done has yielded some results so far. Thanks in advance.