Problem: Vista hides control characters (0080 - 009F) in Unicode TTFfont

Hi,
i have a Unicode TTF Font (HP48.ttf) with some very important Symbols
in the control character range (0080 - 009F) . But unfortunately
Vista does not show them, neither in charmap nor in other
applications. Windows XP shows them flawlessly. The Symbols are still
in the file after font installation as i can see the missing symbols
with an external font viewer.

My question is: How can i let vista show the characters between 0080 -
009F in a unicode ttf file?

If i dont get this fixed i have to dualboot XP every time i need the
font.....

Greetings
Max