I've found a solution to display Calendar Stamp correctly on templates using overrides. There is only one limitation, this create a white gap below the stamp as shown on the picture below :

It's impossible -I think!- to create the layout on the right with the same code on every template because templates use different code! Some use nested tables and others use divs in different ways.

The next update for Calendar stamp will give you the option to generate the code in three different ways:

1. Default Mode:
   This is the mode used currently. It's suitable for templates that doesn't use overrides.
2. Fixed Mode:
   This will use the new fix I made above but will display the gap below the stamp. Recommended for normal users.
3. Advanced Mode:
   Calendar Stamp works by modifying the code in the beginning of the article. This mode will allow you to enter your own code based on the overridden template. Recommended for advanced users who understand how overrides work and have solid knowledge about xhtml and css. I will provide documentaion for this part as soon as It's finished.

I would like to hear your feedback on this solution. Feel free to comment, I am fully open to discussion :) Have a nice day!