I have been using embedded fonts on my PRST1 and I have been using the generic font-family name rather than the specific for the labels, i.e.
Code:
@font-face {font-family: serif; ... etc}
body {font-family: serif; ... etc}
rather than
Code:
@font-face {font-family: "Charis"; ... etc}
body {font-family: "Charis"; ... etc}
I have noticed that the PRST1's font override feature DOES work if you do it this way.
Given that the PRST1's font override feature is less than satisfactory (unpredictable loss of italics/bold) I am rather glad that embedded fonts do work correctly.