I still don't know how to add them, but what you can do is cheat to wreck Regina once and craft a Regina item. Look for it in ItemAttribute and it should look some thing like this.
COMBINATION 0;3;1;4;2;5;3;6;4;7
PS_0 0;1000;9;25000;1;1000
PS_1 16;101;19;101
PS_2 19;2;3;1;4;9999;5;3;6;2
PS_3 14;450;16;101
PS_4 0;138;1;170;3;7;4;3;23;50;6;2
I'm not too sure what the COMBINATION line is for, but I do know what the next lines do.
PS_0 is the Regina feather/wing thingy,
Ex: 0;1000;9;25000;1;1000
Here 0(idk);1000(ATK);9(Attribute);25000(Attribute Variable);1(IDK);1000(MATK)
You can modify ATK and MATK to whatever, but don't mess with 0&1.
Attributes are the fun part!
Here's what I know so far:
1 = Cause Crash
2 = DEF
3 = STR
4 = AGI
5 = INT
6 = WIL
7 = LUK
8 = HP
9 = STA
10-13 = Nothing
14 = ATK SPD
15 = Additional Damage
16 = Crit
17 = Nothing (Crit limit?)
18 = Crit Res
19 = Balance
20 = PvP ATK
21 = PvP MATK
22 = PvP DEF
23 = Town SPD
The number after the ";" is the value of the variable.
Ex
S_1 16;101;19;101
16 = Crit, 101 is the value, so the item provides 101 Crit
19 = Balance, 101 is the value, to the item provides 101 balance
You can also go to heroescontents.db3 and modify the items in "VariableStatInfo"