Passing parameters to callback function of gform_entry

I love this functionality: http://www.gravityhelp.com/documentation/page/Gform_entry_meta

BUT I wish I could send a parameter (in this case, an object) to the call back function (update_entry_meta_callback parameter of the $entry_meta array).

Also, what are the parameters $key, $lead, $form?

OTHERWISE, is there a way to SET THE VALUE of the meta entry while setting the array?
That is, instead of calling a callback function, could I just set the value in the array?

For example, maybe a "has_value" key to the array?

$entry_meta['score'] = array(
        'label' => 'Score',
        'is_numeric' => true,
        'has_value' => 10.43,
        'is_default_column' => true
    );

PS: The anchor links on this page don't work:
http://www.gravityhelp.com/documentation/page/Developer_Docs#Entry_meta

Thanks in advance for any assistance/options.

Passing parameters to callback function of gform_entry_meta