ProDos file type question

[Damian Moser <catfud@mailcity.com>]

    I have a list of the different kind of ProDos file definitions, with their
hex number, and 3 letter type.  My question is, then, how can I change a file
type so that my Apple IIgs recognizes it as what I change it to?
    For example, I can put a text file onto a 3.5 ProDos formatted floppy that
is a BASIC program from my Mac Performa.
    I do have ResEdit, and tried changing file type and creator from there, but
it didn't work.  Is there something similar I could get for my Apple IIgs?