The color format appears to be ABGR; 5 bits per color channel with a 1-bit alpha channel.

ABBBBBGGGGGRRRRR

A = 1
B = 01100
G = 01010
R = 11111

1011000101011111 = B15F

Just use the Windows calculator in scientific mode.

Anyway...


Decimal to binary:
1. result is an empty string of digits
2. if the value is odd, put a "1" in front of the result, otherwise a "0"
3. divide the value by 2
4. if the value is not 0, goto step 2, otherwise you're finished.


Binary to decimal:
1. the result is 0
2. add the first binary digit to the value
3. cut this first digit off; if all digits have been removed then you're finished
4. multiply the result with 2
5. goto step 2

Alternatively, use the powers of 2:
01010 = 0 * 16 + 1 * 8 + 0 * 4 + 1 * 2 + 0 * 1 = 10


Decimal to hexadecimal:
Convert the value to binary, and use groups of 4 bits (starting from right) to get the hexadecimal digits.
Example: 582 => 1001000110 => 246
(hexadecimal digits are 0123456789ABCDEF)


Hexadecimal to decimal:
1. result is 0
2. get the index of the first digit of value (e.g. "F" is 15) and add it to result
3. remove this first digit; if all digits have been removed then you're finished
4. multiply result with 16
5. goto step 2

Alternatively, use the powers of 16:
A3D4 = 10 * 4096 + 3 * 256 + 13 * 16 + 4 * 1 = 41940


EDIT: One of the methods was faulty.

I have finally found out to hack the palettes by myself.
http://rapidshare.com/files/162031775/Mega_Man_Zero_-Blacksith_Zero_Palette_Hack.zip.html

This is just a little demonstration, from what what I have learned.
For those, which use Windhex or other Hex Editors, put not the wanted value as 16bit in the HEX Searcher. If the wanted value is A9AC, put it this way in the searcher ACA9. The adresses goes from left to right and each adress has place for 255 bit. Now I am really tired of my work. I wish you like me good luck.

Sorry  .
It was for me a great experience and I have just simple forgotten for a moment in my joy the rules. It won´t happen again, I promise you Nightcrawler.