settings API: how to create a multi checkbox with blog categories?

i need to create a callback function with a multi checkbox with all the web/blog categories as multi options.

my add_settings_fields are:

   add_settings_field(  
        'select_page',                      
        'Select Blog Page',                         /
        'journal_combo_select_page_callback',   
        'journal_theme_blog_2_col',
        'blog_page_blog_2_col_section'  

    );

    add_settings_field( 
        'limit_posts',                      
        'Limit Posts',                          
        'journal_limit_posts_callback', 
        'journal_theme_blog_2_col',
        'blog_page_blog_2_col_section'  
    );

    add_settings_field(      // $id, $title, $callback, $page, $section, $args
    'check_categories',     // $id  
    'Choose Categories',    // $title 
    'journal_check_cats_callback', // $callback -
    'journal_theme_blog_2_col', // $page
    'blog_page_blog_2_col_section' // $section 
);

do i need to declare some kind of array in settings_field ‘check_categories’ to comunicate with the callback function?

    function journal_check_cats_callback() {
$options = get_option('journal_theme_blog_2_col');

    $pag = journal_theme_blog_2_col;
    $_cats = get_terms( 'category' );

        $html = '';
        foreach ($_cats as $term) {
            $checked = isset( $term->term_id ) ? $term->term_id : '0' ;
            $html .= sprintf( '<input type="checkbox" id="%1$s[%2$s]" name="journal_theme_blog_2_col[]" value="%2$s"%3$s />', $pag, $term->term_id, checked( $checked, $options['check_categories'], false ) );
            $html .= sprintf( '<label for="%1$s[%3$s]"> %2$s</label><br>', $pag, $term->name, $term->term_id );
        }
        $html .= sprintf( '<span class="description"> %s</label>', '' );

        echo $html;
}

EDIT:

well i’m trying to put this code working, but it’s not quiet right yet… at the moment when i click in the Save button (submit) the values are saved in the wp_options table.
For example:

in settings_section i have three settings_fields. One combo box (select_page), one input text fiel (limit_posts) and one multicheck box with blog categorys (check_categories) and bellow is the data saved in wp-options table:

a:4:{s:11:”select_page”;s:1:”4″;s:11:”limit_posts”;s:3:”100″;i:0;s:2:”13″;i:1;s:1:”7″;}

and this is the correspondent array:

Array ( [select_page] => 4 [limit_posts] => 100 [0] => 13 [1] => 7 )

Problems to solve:
1 – the checkboxes don’t stay checked! And of course if i click on save again without checking new ones, the values in the options table are erase.

2 – i also realized that the “check_categories” isn’t save into the serialized value… So i think this is a problem, because i don’t know how to fecth only the array values from “check_categories”

Someone can give me some help?

Thanks,
nelson