The studio item lists for Neo are found at: abdata\studioneo\info. Open the 00.unity3d one in SB3UG, and locate ItemList_00.
You can a) edit it directly in SB3UG, or b) highlight ItemList_00, press ctrl+c and paste it into notepad. Once done you just copy
all the text from notepad and paste it back into ItemList_00 with ctrl+v.
The list for NEO is a bit different, but not too different.
You'll have to add this at the end of every line: <><False><False><><False><><True>, along with removing the empty <><> at the beginning of each line.
Neo doesn't have a line ID, so items works as with everything else in regard of IDs, you don't need
to worry about ID gaps i.e: 01, 02, 03, 10, 11 etc.
If you want to, you can put the HH stuff in their own category.
You can add your own categories by editing ItemGroup_00. That one is
simple to do.
Add this line to the bottom of the list in ItemGroup_00:
<14><Honey Horror>
To get the HH items to end up in it you edit this in the ItemList_00:
<15025><1><Slime Pool 04><><studio/itemobj/honey/sit_HoH_s1.unity3d><slimepool_04><><False><False><><False><><True>
<15025><14><Slime Pool 04><><studio/itemobj/honey/sit_HoH_s1.unity3d><slimepool_04><><False><False><><False><><True>
It might sound all compicated and stuff, but it is really easy to do all of this. Just keep an eye on what you do.