Well of course you have to have JPAN's hacked engine. He repointed the table to 0x1A2400. It keeps the same format of the original, PPPPPPPP nnnn0000. P= Pointer, N=Pallete Number. So say you wanted to add a new pallete and have it located at 0x800000, you would do this. 00008008 20110000. Thats what you would add to the table. I dont know what the 11 does, but the 20 is hex so it makes the pallete number 32. Make sure you end the table with the 00000000 FF110000 or else it wont work.
Now go to 0x800000 and place youre pallete data there. What I do is edit the pallete of an original one in NSE and copy down the hex data and paste it to the 0x800000.
Code:
0E 53 9C 5F 10 2A B1 2E 58 57 89 2D 8D 3E F2 56
FC 3D DE 7F 31 46 0C 3A 54 25 B9 3A F3 31 C6 18
0E 53 5F 5B FE 4A 5B 3A 0F 21 9F 5A BA 3D 11 29
12 77 0C 66 E7 24 18 6B 31 4A 29 2D FF 7F 00 00
Thats the first pallete I have in my table. Also go to the overworld you want to edit and change its pallete numbe to your new one. Edit the sprites.ini file in OW:RE to &H11A2400 and open it up. Go to the sprite and there it is.
If anything is unclear say so, because I am kinda tired right now. Its also been months since I have done this.