getRTFBody() does not render special characters (öüäéèà" etc.)

[CorinneKnoe]

Some emails I have to read with getRTFBody(). I only need the plain text, however the text can be written in various languages, that is it can contain [öäüéèà] and so forth.

I had a look at the LZFu class. However, changing line 64 (charsetName from "US-ASCII" to "UTF-8") didn't help. Is there a simple way to get the decoding right?