Decode base64 to job CCSID?

I'm trying to decode a base64 string. It's giving me the results as *UTF-8
when I need *JOB CCSID. Can someone point out what I'm missing?

Thanks

Dcl-proc DecodeTest ;
Dcl-pi *n like(retDecoded) ;
encoded varchar(1000) ccsid(*UTF8) const ;
End-pi ;

Dcl-s retDecoded varChar(1000) ;

EXEC SQL
set :retDecoded = QSYS2.BASE64_DECODE(:encoded);

Return retDecoded;
End-proc ;