Hey Chimera,
How do you actually get to get them naked ? For me, still all normal clothing is as normal, Pantsus are working, but no Nudity.
Well you need to understand how armors actually work. Essentially when you equip an armor, it is removing your base body and replacing it with a body mesh that it had included with the armor.
Because of that and the fact that most armors are very well optimized and have very little of the body mesh left underneath them, very few armors can be made actually nude. The only cases where they can be made nude are when the designers of the armors did not cut out the crotch or thorax of the character for optimization purposes.
So only some armors are bare breasted or without panties. Usually all I or anyone else are able to do is make them a bit more skimpy by raising the clothing line up to the limits that the body underneath allows. If we cut out anymore than that, you'd see invisible holes in the body.
__________________________________________________
tl;dr:
Only some armors are nude, and very few at that. You'll have to experiment and see which armors are or are not nude.
Using the Fashion Coupon store and CTRL+Right Clicking on the item to open the preview screen is the easiest way to view armor looks, while you can simply use the Dressing Room to check out how a costume looks.
Occasionally the devs forgot to add a costume or two to the Dressing Room, though, in which case your only option is to check the Broker to see if there's a listing in there and use the CTRL+Right Click function to preview it.