Today i had two new ideas.

1. Seperated the tables in to two tables, deleted the body 0 margins to get back reply paddings and pushed the second table to the left edge:

<table1 width="100%">email regular text</table>

<table2 width="120%" style="margin-left: -30px;">footer signature</table>

Result: Works, reply text has normal paddings again, but on some email clients still tiny small white paddings. Because of the width 120% the email window gets scrollable horizontally:

2. Deleted the body 0 margins and seperated the tables in to two also. Put a fat outline around the second table, colored in footer bg color

<table1 width="100%">email regular text</table>

<table2 width="100%"style="outline: solid 25px #98DBCE;">footer signature</table>

Result: Works, but on some email clients still tiny small white paddings too.

I am searching for better Ideas :(