[development] filtering empty dates in views

I have a custom module with a custom date. After searching through drupal.org I save dates as timestamps in integer fields. Now I need to create a view filtering nodes with empty date; how should I do this? I have added to views_handler_filter_numeric.inc (views_handler_filter_date.inc depends on it) the option to choose greater, equal, less..., null and not null. Is this the correct way? any other ideas? -- *La vida és com una taronja, què esperes a exprimir-la? *Si creus que l'educació és cara, prova la ignorància. *La vida és com una moneda, la pots gastar en el que vulguis però només una vegada. *Abans d'imprimir aquest missatge, pensa en el medi ambient.