Reply format of emails - HTML

Hello,

I have the following problem: (Sorry for asking if the problem has already be covered in this forum, if so I did not find it)

When I reply to an email that is HTML formatted and I chose the option that includes the original message my text is formatted the same way the original message is formatted (font, size, color).
When I do not include the original message the settings which I have defined for the compose view (HTML) are used.

Standard reply format is set to HTML Enhanced

I want that all my replies are formatted the same way the messages which I compose are formatted no matter if the original message is included in the reply or not.
What do I have to do to achieve this?

Thank you in advance
Martin