Hi Jaap,
It is possible to do this, but this is a bit advanced. There two ways to achieve this.
1) via the tag, on the page "/Jaaps_website//Welcome_files/widget1_markup.html", you can tell the tag to ignore the page URL and pass a value explicitly when calling
_trackPageView. For instance, instead of having the code _gaq.push(['_trackPageview']); , you can use the _gaq.push(['_trackPageview', '/']); This will tell GA to use '/' as the url of the page instead of "/Jaaps_website//Welcome_files/widget1_markup.html". Be sure to only change the code on the page "/Jaaps_website//Welcome_files/widget1_markup.html" - otherwise, all of your page url's will be overridden.
2) via the profile admin interface, you can create a filter to tell GA to replace the page URL "/Jaaps_website//Welcome_files/widget1_markup.html" to "/". Here's a screenshot of how this can be done.

Hope that helps. Good luck!
Lothaire from the Google Analytics Academy Staff