[XeTeX] Change font metric?

[Thierry]

OK, I understand that it is not possible!
To answer to some of you, here are some details:

- the fonts with the problem are (so far) Minion Pro and Adobe Jenson Pro. I really appreciate them, so that I would like to use them.

- xetex (and pdflatex, and latex) changes U+0027 in the source to U+2019 in the pdf output (copy/paste the text from the pdf output to see it in action). This is a clever change, because this is the right apostrophe to use. So, no need to use U+2019 in the input. Moreover, U+0027 is easy to access on the keyboard, not U+2019.

Thanks for all the comments and advices
Thierry