HTML 5 tags not recognized in internet explorer

I am using internet explorer and I came across some issues while theming my omega sub theme.

Internet explorer does not process the HTML 5 tags when it finds it.

For example : this tag ( do not confound with will become . The style associated to it will still be , but the block will have a width and height of 0px , making it impossible to theme.

After doing some research I found some solution :

I use this simple module which will only insert a script from remy sharp into every page head. This script will activate only on non-compatible version of internet explorer and will "help" internet explorer to render HTML 5 tags.

http://drupal.org/project/remysharp_html5shim
This module or script could be intergrated into omega.

After getting feedback , I have been told that the script html5shim is already included in html.tpl.php and I might probably have overrided it using a preprocess function ( mytheme_alpha_preprocess_html(&$vars) ) in preprocess-html.inc

Finally , the file implicated in the disappearance of html5shim script was html.tpl.php in my subtheme templates.
I removed it and updated the cache and it worked fine without the module.

At the moment I didn't modify the html.tpl.php so that s solution was fine for me since I am using the preprocess function.
However , I still wonder if you want to create your own template how to manage that issue. I didn't find at all where html5schim script come from in omega themes code ( didn't find the string in any of the theme file ).