Hyphenation of german words and em-dashes in german texts.

["Robert F. Beeger" <5beeger@informatik.uni-hamburg.de>]

Hi!

I've got two questions:
1. I've written a file that contains the hyphenations of some words I often 
use and which TeX seems not to know how to hyphen.
     All works wonderful until one of the words contains an Umlaut as in
         \hyphenation{Prä-sen-ta-tion}
    Then TeX says
         ! Improper \hyphenation will be flushed.
	\dohandleaccent #1#2->\def
                            \glyph {#2}\ifx \glyph \empty \dohandleaccent 
#1\...
	l.1 \hyphenation{Prõ
                     -sen-ta-tion}
	? h
	Hyphenation exceptions must contain only letters
	and hyphens. But continue; I'll forgive and forget.
   It doesn't work with \hyphenation{Pr\"a-sen-ta-tion} either.
   Is there a way around this problem?
2. In the TeXBook I've read that an em-dash is to be used in a sentence 
like "Every land I've ever visited has its own god --- or its own set of 
gods --- and they all have different names" From the moment I've read this 
thing about em-dashes in the TeXBook, I began to really discover them in 
english texts but never in german ones. Is this a special rule that is 
valid only for english texts or is it also a rule for german texts. And 
have I then, up to now, read only badly typsetted german texts? :)

Greets
     Robert F. Beeger