printing superscript and subscript unicode characters in zpl

this code will print a Hallo string followed by a supercript 1:

^XA ^CI28 ^LH0,0 ^PW431 ^LL144 ^FO1,31^AQ^FH^FDHallo_c2_b9^FS ^XZ

Now, I would like to be able to print also the other superscript unicode characters, such as e281b4 (the number 4), but it seems like zpl only supports number from 1 to 3. Can anyone give me a suggestion ? Thanks