Hagen,
> gpdemo=# \encoding
> UTF8
UTF8 includes virtually all characters you will need for any purpose on
the earth.
But: you showed the output of \encoding when you were asked to show \l .
There is a subtle difference:
\encoding shows the encoding of the connection between psql and the
server; while
\l shows the encoding the database server will actually store the data in.
While the first can easily be changed for a session, the latter can only
be set when creating a database (or a cluster).
-hannes