Willabong

When trying to display some symbols that appear above letters on my WM5 PDA, eg:- ˉ ˘ ` ´ The later 2 symbols are ANSI and Unicode, the first 2 are Unicode only.
So I find that I can only display 2 of the 4 symbols shown here.
The problem is that Windows Media devices will only show ANSI symbol code correctly, but Unicode symbols do not display.
I work with over 3000 people who require PinYin Chinese text on their PDA's.

So is there a reg tweek or a method of installing a required font, to enable these characters (symbols) to display properly?
Any help would be wonderful?