Getting Ogone to use my Joomla template

I know it's possible to get the Ogone payment pages to open in my website and i found the option "dynamic template" to make Ogone look for the template but exactly do i do that. You guys have it done here on the website i noticed. I made an article in Joomla with just the $$$PAMENT ZONE$$$ code in it. I copied the exact link in the Ogone Payment Gateway and then tried it. I did almost what i wanted, it showed the payment page in the website but there was no CSS applied
The link was to a .php as it is a dynamic website but when i read the Ogone guidelines (which are very limited, atleast for me they are) it should be a .html
How do i do that?
Hope u can help me with this one, even if isn't really a CBSBUBS problem but since i noticed you did it on this site i kind of hoped you could help me out.
Thx in advance!

We have made our urls absolute for our template.

So i need to change all links in the .html version to their full version?
Do i understand that correctly? Even those of scripts etc...

Yes, indeed, as you are on a different base url, all the urls in the html source need to be absolute.

We do e.g.:
To add a CSS file in a clean way (Joomla 1.5) in our template.

Thx 4 the quick help.
Can i just take the sourcecode of a displayed page and save that as a .html, then change all links that are in the code to their absolute version ("http://mydomain/.....)?
Or is it possible to just use the index.php as reference? I guess not as it is stated that .html is needed.

Yes, of course, both are possible.
- using index.php makes it more adaptative
- using a static html page is the recommended way by Ogone, as it's faster to load.

Avoid javascript if possible, and limit css files, you want that page to load fast, as fast pages give higher confidence and increase conversion rates.

If you make it dynamic and non-static, make sure your site and host passes PCI-DSS scanning tests, to be on the safe side.