I give much credit to the original creator of INVedit .
All I did was edit the items.txt and add the arrows' corresponding pictures to the folders but it works to add any of the modded arrows. I also added the horse saddle from the Mo' Creatures mod.
Oops sorry guys, forgot to even post the link the first time. K here it is. http://www.mediafire.com/?u4y4bkj0if7285u
If anyone wants to know how to add an item from a mod yourself then here is some information on doing it.
There might be some variation depending on what you want to add to the list.
So in your INVedit folder, there should be INVedit.exe, some png's, NBT.dll, and items.txt. If you open up items.txt then you should see a Blocks section, and Items section, and a groups section.
The Blocks section is obviously for any block in the game.
The ID column is the id # of the block itself. The NAME is the name of the block as it appears in INVedit. Don't use caps except for the first letter and don't use spaces, use underscores or _.
The FILE column is for specifying which picture it should access to find the block's icon. and the CORDS column stands for coordinates.
Most of it is self explanatory except for the CORDS.
CORDS work like this.
The X Coordinate comes first, then the Y Coordinate. Like this x,y 0,3 (=Grass)
I don't know how many pixels it considers one unit for these coordinates but if someone else does please post it below. The only way I have discovered to find the ID's of modded objects is to either find it on the creator's forum or get it in the game somehow, and have it in your inventory. When you open up your file in INVedit, it will show a blue sort of circle with a number in the middle. That number is the ID. Whenever you are adding any value in the ID column, make sure they are right aligned. NAMEs are left aligned. FILEs, CORDS, and DAMAGE are left aligned as well.
Anyways, thats all you need to know for the Blocks section.
The Items section is basically the same except that it adds a DAMAGE column. If the modded object is an item that is like another default item. For example, the obsidian tools mod, just find the corresponding items type (pickaxe, axe, shovel, etc.) above that are made of diamond and Steel and put the damage value somewhere in between the values of the two others.
If an item is stackable in game, then leave its damage column blank, otherwise, the # of that item in INVedit will show up red if it is more than one. It won't affect the item in game but it's just nicer if everything works correctly. If the item does not take damage and is not stackable then put a 0. Always put at least 2 spaces in between columns.
The last section is the Groups section. These are the button toward the middle right side that you can click on to show only certain items in INVedit. After you add your modded items to the lists above, you can choose either to add them in a new group or put them in one of the existing groups. If you want to put them in the existing group then just type in their corresponding ID's in the ITEMS column separated by a single comma (no spaces in between, just a comma). If you want to make a new group then start a new row with a tilde ~ (shift + the button about tab on most computers).
Then add a single space and the name you want to make for your new section. AND AGAIN make sure there are at least two spaces in between the NAME and ICON columns. All columns in this section are left aligned. The ICON column is where you put the ID of a single item that you wish to represent your group. This item will be shown on the group's button. Then have 2 spaces, and then list the ID's of the items you want to add to this group. If you want to add your items in a new section then just copy the format of the section above and replace Blocks, Items, or Groups with a name of your choice.
There you have just added modded items to INVedit yourself. Congratulations.