New Item Creation Help

Kyp

Hello. I was getting into BG2: EE and was a bit underwhelmed by the number of high quality longbows, so decided that I'd like to try my hand at creating one, but haven't found a good amount of information about how to do it. I am currently using NearInfinity and have read about other tools, but for now would like to stick with NI. I'm still working on the in depth description, but the general story is that it was made from a fallen limb, as no blade could damage the tree, the sole survivor of a battle between insane wild mages, a tree that absorbed the various forms of magical energy which became a part of the tree. The stats that I would like it to have are:

Longbow of the Maelstrom

Description

STATISTICS:

Equipped abilities:
– Rapid Shot
One extra attack every two rounds

Charge abilities:
– Create Maelstrom Arrows once per day
Stack of 40
Arrows vanish after 1 day

Combat abilities:
– 5% chance to cast Chain Lightning

THAC0: +2
Damage: +3
Speed Factor: 2
Proficiency Type: Longbow
Type: Two-handed
Requires:
15 Strength
15 Dexterity

Weight: 1

Usable By
Chaotic Alignment
Archer

Maelstrom Arrow

Description


STATISTICS:

THAC0: +2
Damage: 1d6+2, 1d4 fire damage (Save vs. Spell for half), 1d4 ice damage (Save vs. Spell for half), 1d4 acid damage (Save vs. Spell for half), +1d4 electrical damage (Save vs. Spell for half)
Damage type: Missile
Launcher: Longbow of the Maelstrom(if used in another bow, they explode dealing 1d4 fire damage (Save vs. Spell for half), 1d4 ice damage (Save vs. Spell for half), 1d4 acid to everything in a 5 ft radius)

Weight: 0

Any help or advice would be greatly appreciated.