Order by custom field meta_key date and then by custom file meta_key number

I’m trying do order a custom post type page by 2 variables:
– first is the custom post type meta_key “date”
– then, for posts with the same date, it should be ordered by meta_key “number”

I’m willing to set for some kind of ordering on the second level but right now it really seems random:

 <?php $my_query = new WP_Query( array( 
                              'post_type' => 'product', 
                              'meta_query' => array(
                                          array(
                                                  'key' => 'options_type',
                                                  'value' => 'Denim'
                                                  ),
                                      ),
                               'orderby'  => 'meta_value',
                               'meta_key' => 'options_date',
                               'posts_per_page' => 50 ,
                               'order'    => 'DESC'


                              )); ?>

Even editing the “wordpress publication date” doesn’t affect the “same day” order. So I end up with:

• 09.03.2012 244 Diesel (wordpress date 3.8.2012)
• 09.03.2012 246 Levi’s (wordpress date 3.9.2012)
• 09.03.2012 247 Evisu (wordpress date 3.10.2012)

(i’m using european date displayng, so 09.03 means March, 9th)

edit

just to clarify:
I’ve some custom field and i’ve set a specific options_date field for the custom post type, which is different from the wordpress date.

I would like to order the posts using a multiple order: custom field “options_date” and, inside the same “options_date” by another custom field “options_info”.

ordering with

'orderby'  => 'meta_value date',

doesn’t seem to work and it’s not the target result, I’m looking for a multiple meta_key ordering.