Christof Spitz <christof.spitz@gmail.com> writes:

> #+TITLE: SUBJEKT
> #+AUTHOR: Christof
> #+OPTIONS: H:4
>
> * Headline 1
>
> ** Sub 1.1
> ** Sub 1.2
>
> * Headline 2
>
> ** Sub 2.1
> ** Sub 2.2
>
> Branch "Headline 2" should be place to the left of the central SUBJECT
> in Freemind.

It is getting placed rightly.

Here is the screenshot of what I get (with no additional customizations
at my end).  I use freeplane, btw.

As for styles, you need to customize your styles in Freemind exporter
and move over the XML to ox-freemind.el.  If you have a specific
question wrt style, I can help.  But I need to be convinced that you are
using the right exporter i.e., no installation issues etc etc etc.