Menu callback: programmatically submits a form within a batch.
function batch_test_nested_drupal_form_submit($value = 1) {
// Set the batch and process it.
$batch['operations'] = array(
array(
'_batch_test_nested_drupal_form_submit_callback',
array(
$value,
),
),
);
batch_set($batch);
batch_process('batch-test/redirect');
}