PostScript files: textconv and "git add -p"

Hi (and happy new year everybody !),

I have trouble setting up a comfortable configuration to version PostScript files. The particularity they have is that they are "text files" (i.e. git does not detect them as binary files by default, and neither do tools like less, diff, ...), but not meant to be human-readable.

If I do this:

,----[ .gitattributes ]
| *.ps diff=ps
`----

,----[ .gitconfig ]
| [diff "ps"]
|       textconv=ps2ascii
`----

then I get the textconv niceness when running "git diff", which is cool, but "git add -p" still proposes me to stage hunks one by one, which isn't.

If I set "*.ps binary" in .gitattributes, "git add -p" becomes quiet, but textconv is disabled.

I want "git diff" to run the textconv filter, and "git add -p" to consider the file as binary. Is there a way to do this?

Thanks,