how to install a add on when you don't have the updates to the code

[Tidbeck]

I would like to install the add on: http://addons.oscommerce.com/info/6505 but i don't have a clean installed version of oscommerce 2.2. I have the add ons option types, center shop, and some other safety add ons already installed as well as a modified stylesheet.

 

Is there a way to figure out how to install this add on without the code updates (this add on file has a installer.php file, i have not installed an add on with that type of file before)

 

Any tips much appreciated

 

Elin