It took about two years (i started blogging end of December ’07), but i FINALLY figured out (by accident) how to have new blog posts automatically include my customized signature in blogger.
I have been searching online periodically but never found the answer, and then tonight i was just playing around with settings and stumbled upon how to do it. I know i’ve been trying to figure it out for a long time, so chances are that some other people are too. I’ll share the steps here:
1. from your dashboard, click on “settings”.
2. click on the “formatting” tab near the top
3. scroll all the way to the bottom, to where it says “post template”. type in the html code for your signature and click on “save settings”. In this space, you can enter whatever you want to be automatically included in each of your new posts, and not just a signature.
Hope this helps!