Where to exchange Favicon.ico

How to change favicon.ico, I have not found where it is?
Favicon for Joomla is in template, but where is favicon to hotjoomlaextensions ?
We use Joomla eCommerce template.

I think this must allready be an answer in this forum but I can't find where to search in the forum.... (IE8)

I also want to edit the startpage showed when site is closed. The message is easy to change, but how to exchange Joomla logo to our logo.

We don't supply favicon.

Here is official link for how to change it.
docs.joomla.org/Changing_the_site_favicon