Thank you very much for your question and the print. You are correct in looking for the symbol in UEB 4.2 Modifiers since this is simply a foreign name appearing in an English context. In this instance, I would advise you to use the first transcriber-defined modifier ⠘⠸⠂ placed before the letter and list it on the Special Symbols page as "double acute accent above following letter" because as you noted, it is not one of the modifiers provided for in the list.
The name, in uncontracted UEB, would be transcribed as follows:
Please let me know if you have any other questions.