If you notice, it tells you which palette it is in the map viewer. It ranges from 0 to 15, in the screenshot it even shows that. (So you don't have to search.)
Just edited your screenshot.
Also, if you guys want to edit the palette manually, there is a way. I figured this out about a week ago.
First, you get each color of red, green and blue.
Let's say you wanted to make the RGB of 22,37,103. First, you have to round off to multiples of eight. (Meaning if you divide the number by 8, there will be no decimal/remainder.) So, my new numbers are 24,40,104. They are all multiples of 8.
Now, you need the windows calculator. In Windows XP, it's located Start>All Programs>Accessories>Calculator. Once the calculator is open, you need to change to Scientific view.(View->Scientific)
Next, make sure you have decimal selected("Dec").
Now, first divide each number by 8 and we have the valid numbers we can use. So, with the numbers I had before, this gets me 3,5,13. The numbers only range from 0 to 31. The numbers will show up in the game as multiplied by 8.
Now, convert these numbers to binary, by first typing them when decimal is selected and then clicking, "Bin". You'll get a series of 1's and 0's. If the number you get is less than 5 digits long, you'll need to add zeros to the left of the number so that it is 5 digits long.
For example, '3' converted to binary is '11,' so the number you need is '00011.'
Now, with all three numbers converted, now my values in red, green and blue are 00011,00101,01101. Now, the next thing you need to do is simply reverse the numbers so it is now blue, green, red(instead of red, green blue). So, now I have 01101,00101,00011(13,5,3) of blue, green, red. This is your binary code version of your hex colors.
So, remove the commas and the code is '011010010100011.' Now, type the full 15-digit code into the calculator while in binary("Bin") mode. Then, click "Hex" to convert it to hexadecimal. In my case, I get 34A3 as my hexadecimal code. Now, reverse the bytes and instead of 34A3, you now have A334, this is the code as it would appear in the hex editor. Now the first post tutorial can help you with the rest.
(I think that tool was made simply to help with this step.)
And, also instead of writing down the hex codes for every single palette color, it's easier just to rip the whole thing. First, get the address of the first color in the palette you're editing.
Then, open the Memory Viewer(Tools>Memory Viewer in VisualBoyAdvance) and click "Save..." Then, type in this address with a size of 20(Hex for 32) and it will save a .dmp file.
Open the .dmp file with a hex editor and the entire palette is put there for you already. You can simply copy the entire thing and then search for it in the rom to find the palette.