As many of you no doubt know, cBliss as a code is not compatible with BrawlEx. There is, however, a way to achieve the same effect using the Fighter and CSSSlot Config files.
If you want to simply have every default character with 10 costumes, you can download
these stock files I created and copy them to their proper places in the BrawlEx directory. If you want to have a custom number of costumes or different numbers for each character, or have them ordered differently, the tutorial below will explain how to do so.
You'll need a hex editor in order to edit the CSSSlot Config files in addition to the standard BrawlEx files and Config Utility.
First, you should use the BrawlEx Config Utility to open the character's Fighter Config. Check all of the costumes you want used for the character. Do not check or uncheck ?A or ?B, as we don't know what those actually do as of yet. Also keep in mind that checking more than ten costumes (usually 0 - 9) will cause the last one or two costume's cosmetics to overlap with the next character.
There are a few characters that can have more than 10 without conflicting cosmetics, however, because the slot after theirs is empty or dummied out. These characters are Ganondorf, ROB, Wolf, Toon Link, and Sonic.
Save it and close.
Next, open up the character's CSSSlot Config file. The last two lines here are what we're going to be working with. Each set of two bits (a bit is composed of two characters) determines a costume. So a set of four numbers is a single costume, here. At the end of the costumes is the bit 0C, which indicates the end of the costume set.
Now, the two bits for the costumes work like this: The first bit indicates the Costume Color and is used to indicate Team Colors. 00 Indicates Red Team, 01 indicates Blue Team, and 03 is Green Team. Any other number for the first bit will not affect them.
The second bit determines the costume number that is loaded. 00 will load FitFighter00, 01 will load FitFighter01, and so on. So, a set of bits reading as 0001 would indicate a Red Team costume which will load costume 01.
The order that you place the costumes in the file will determine the order they scroll through. So the first costume you put in the file (typically the default) will correspond to the first portrait in your sc_selcharacter or common5. The second costume you type will correspond to your second, etc.
One more thing I should mention is that the game will not give more than one set of Team Colors to any given character, as each one is hard-coded to only have one set. It will read the first set, but won't acknowledge the second as Team Colors. The exception is Wario, who has a very specific order to his Team Colors. In my experience, he will freeze when scrolling through his Team Battle portraits unless his Team Colors are arranged as Red -> Green -> Blue -> Red -> Blue -> Green.
When you've arranged your costumes to your satisfaction, save. All that's left to do now is to add the portraits for your new costumes. Make sure you include CSPs, BPs and RSPs. If you intend to use the characters in any single-player modes, you must also add Stock Icons.
And that's it! I'll be glad to answer any questions.