No, in your server files, you should find a data folder. In there, there should be a folder named "def" (short for definitions).
Go into that folder and then go into "txt", find items.txt and open it.
Search for the item using its id or name, and then change the equipment type to platebody.
In this case, since you are changing Vesta's chainbody, the ID is 13887.
Code:
Item Id: 13887
Name: Vesta's chainbody
Examine: This item degrades in combat, and will turn to dust.
Value: 2410000
Stackable: false
Noted: false
Double-handed: false
Equipment type: BODY
Is Weapon: false
Bonus[0]: 5.0
Bonus[1]: 7.0
Bonus[2]: 7.0
Bonus[3]: -15.0
Bonus[5]: 120.0
Bonus[6]: 131.0
Bonus[7]: 145.0
Bonus[8]: -3.0
Bonus[9]: 140.0
Bonus[10]: 60.0
Bonus[11]: 6.0
Bonus[13]: 12.0
Bonus[14]: 6.0
Requirement[1]: 78
finish
As you can see in the definition above, the equipment type is set to "BODY", which obviously is wrong.
Set it to PLATEBODY instead. Like this:
Code:
Item Id: 13887
Name: Vesta's chainbody
Examine: This item degrades in combat, and will turn to dust.
Value: 2410000
Stackable: false
Noted: false
Double-handed: false
Equipment type: PLATEBODY
Is Weapon: false
Bonus[0]: 5.0
Bonus[1]: 7.0
Bonus[2]: 7.0
Bonus[3]: -15.0
Bonus[5]: 120.0
Bonus[6]: 131.0
Bonus[7]: 145.0
Bonus[8]: -3.0
Bonus[9]: 140.0
Bonus[10]: 60.0
Bonus[11]: 6.0
Bonus[13]: 12.0
Bonus[14]: 6.0
Requirement[1]: 78
finish