[imp] Umlauts and character problems with html mails

[norbi]

Hi List,

i cant see umlauts in emails, they was composed in html.
umlauts in the subjects are no problem, umlauts in text-mails are no 
problem, only in html, i cant see umlauts.

horde 5.0.4
imp 6.0.4
browser: firefox 19 / ie 9

any hints, where i have to search for fixing this ?

i see somthing like this :

sagalnsgdnasdg#
sadgÀöÀöÀöasg

asdg
ÀöasÀ
gösÀa
dgÀösa
dg

norbert