How to set the value of my checkbox?

hey all,
I’m have a HABTM relationship and I’m trying to use checkbox.
The problem is that I can’t set the value of each checkbox sad each
checkboth value gets set either to 1 or 0 depending on whether the it
is checked or not. I would like the value to be equal to the id of my
model.
This is how I do it:

<% for cat in @categories %>

<%= cat.name%>
<% for forum in cat.forums %> <%= check_box(:forums, :id ,:value=>forum.id, :checked => (forum.users.include? @user) ? 'checked' : false ) %><%= forum.forum_name %>

<% end %>

<% end %>

I also tried without the :value=>forum.id but still nothing

Any idea?

thanx in advance

Pat