[themes] Theming forms in a table

Hello I am trying to insert a form in a table. I want the result to be similar to module table admin->modules. I have read some topics in drupal home page like: - http://drupal.org/node/82916 - http://drupal.org/node/97361 - http://drupal.org/node/47582 (the last comment is very clear) I have got to insert the form but when I click in the button (submit) in form_id_sumbmit function I do not receive this element values. What am I doing wrong? Regards