LineFeed character is displayed in Isabelle Proof General

[Bastian Reich]

Hey there,

I'm currently trying to get the Proof General font-end for Isabelle 
working with (x)emacs21(-mule).
Proof General integrates an interactive shell into emacs.
When I press return while being in that shell, the LineFeed characters 
are directly displayed on the screen.

Example:
> welcome;
Welcome to Isabelle/HOL (Isabelle2009-1: December 2009)
> ^AS

pressing return again:

> ^AS

Other Escapecharacters are displayed as well.

I already switched the buffer-file-coding-system to utf-8.
Or is this a (configuration)problem of Proof General and not emacs?

Cheers
Bastian

--
locale
LANG=en_US.utf8
[...]
LC_ALL=