Josef Dalcolmo <dalcolmo-pAMK5YC0Xik@public.gmane.org> writes:

[...]

> I spent the evening looking for the right parameters to adjust - but
> did not find them yet. Any hints?

mailcap

Dunno how to handle it on Windoze, but the *first* hit of 
  M-x apropos RET mailcap RET
brings you to the appropriate customization buffer.

Greetings,
Jochen
-- 
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