How to use Lightbox with Insert styles?

Hi there,

I have been using the Lightbox2 module for years on Drupal 6.x, and was truly happy with it. I recently decided to upgrade to Drupal 7, but there are some features that are not there anymore. I used to be able to insert images through the "Insert" modules, and the drop-down menu allowed me to choose the sizes I wanted to use. I can't find this option anymore - I had a look into the field settings and I can't find any "Lightbox" styles in the "Insert" section of the field in my content type page. When I go to "Manage display" I can see them though. Is there something I am doing wrong? I have a lot of content and I don't want to switch to another module! :)

I found this page mentioning a similar problem: http://drupal.org/node/1466264 but no information was given either.

Thanks for your help.
- Tim