If those funny symbols only appear on the jacket, you would braille them as accented letters (with a dot 4 preceding the accented letter), according to literary braille. You would have to put in a transcriber's note stating the change. If it was throughout the text, you would assign it a symbol, and place the explanation on the Special Symbols page. If you are brailling this book according to formats, you would need to post your question there ...
In literary braille, no matter what funny symbol is being shown with any of the letters, all are brailled using a dot 4 before the letter marked with an accent or funny symbol in print.
I hope this helps.