View filter on date "Less than or equal" AND NULL(empty)
Well I could figured out this for myself, if anyone need it here is what you need to do:


Go to sites/all/modules/views/handlers/views_handler_filter_numeric.inc
In there: 

a. Inside the function operators()->$operators = array(

b.   

'custom' =&gt; array(
'title' =&gt; t('Title you want for your operator'),
    'method' =&gt; 'op_custom',
    'short' =&gt; t('&lt;='),
    'values' =&gt; 1,
 )



c. Then around line 255 or so create a new function:

function op_custom($field) {
  $or = db_or()
  -&gt;condition($field, $this-&gt;value['value'], 'IS NULL')
  -&gt;condition($field, $this-&gt;value['value'], '&lt;=');
  $this-&gt;query-&gt;add_where($this-&gt;options['group'],$or);
}


And you can choose that operator now in your Data Filter.

I hope this helps, any questions let me know as PM or comments, take care