yep,you have the option to add a new unit.
to add a new weapon the three warscape_equipment_....... - tables are the right ones.
i dont know it,but i think :
when you add a Katana in your equipment.max file,you have to give it a unique name.
lets say, rigid_equip_mykatanaLOD 1,2,3,4 for example.
then you have to open the warscape_equipment_collections table,click on add,an write " mykatana " ( the name you chose in the equipment file ),then click apply.
then open the warscape_equipment_items table,click on add,and again write " mykatana " , then under the equipment_key Tab choose " my katana " ( your new equipment-collection you create before )
click on apply.and now open the warscape_equipment_themes table,click add,and write mykatana again.then choose the primary weapon,secondary weapon .......et cetera .
let me know if you try this.....
and the textures.....i think,there is a mesh1.variant_part_mesh and a mesh2.variant_part_mesh,so maybe you have to make a new equipment file,named " mesh3.variant_part_mesh " to add new weapons without
deleting the others.if this is correct ( i dont know ) , maybe it is the same with the texture1diffuse and texture2diffuse,so you have to make texture3diffuse ( this is the texture of your weapon ) ...........
if this is true,you have to make this step again for every single weapon ( mesh4,mesh5,......... )
but perhaps this is not correct........
and the other question,you can place a helmet in the "masks " or "back" folder too,and use it in Unit Editor.but watch out ! a helmet used in the " legs " categorie will maybe not work........
Regards