[Solved]hierarchical select: how to get the current term id?

Hi,
I am just trying to put together my first module, ...
I created a formulaire for the end user consisting of a dinamic graph, a dropdown menu and a submit button ...
In the drop-down menu I display a vocabulary, and I used a hierarchical select widget(hierarchical_select module)

Now, how could I get in my PHP code(in the Submit buttton handler of my module), the current term id of the current selection of the hierarchical select (hierarchical drop down)?

For a simple textbox for example a code like:

$note = form_state['values']['note'];

would put in $note the user's entry of that textbox ..., but this code is not working for the selection of my widget, although I just need something like this for my drop down field ...