I figured out how to edit jersey numbers in NBA 2K12 for PC, which means I can make fictional jerseys now xD
Anyway.
First off, you will need to download the following program:
viewtopic.php?f=143&t=83389
MAKE SURE YOU DOWNLOAD THE LATEST VERSION, IT IS THE 12/15 VERSION, OR ELSE THIS WILL NOT WORK.
Extract to your desktop.
Open up the Mod Tool.
Then open the jersey you want to edit the number of.
(The first menu on the left, then the first drop down option. Go to your NBA2K12 folder and select the jersey.)
Now go to the number file inside the jersey.
Right click the number, and click the third option going down to save the number. MAKE SURE YOU SAVE IT AS A PNG. AND NOTHING ELSE BUT A PNG.
Save that to your desktop.
Then open the file up in gimp, photoshop whatever, and edit the colour of the numbers. Once done import the number back into the mod tool via selecting the 4th option to be selected. Then repeat for the letters.
Once you are done with all that, go to the menu on the left, click and select the third option going down to save as. Save it to your desktop, and replace the jersey with an edited numbers and letters version. DON'T FORGET TO BACKUP.
Hope this helps.