Custom Entity API does not give individual fields in Views, only (sometimes information-less) rendered entities
If you've tried conventional approaches and they haven't worked (like me) then you might find that there are a few things that you need to do:

Firstly for me was truncating the cache table just to get rid of a whole heap of old data from previous iterations of my designs. Then it was simply defining hook_entity_property_info as suggested. To check if things are working you can debug and use hook_views_data_alter(&amp;$info) and check out the variables. You'll probably see views has two varieties (unless I'm still doing something wrong):

entity_subscription and views_entity_subscription...

entity_subscription Array [3]   
    table   Array [2]   
        group   Subscription    
        entity type subscription    
    user_id Array [4]   
        title   user id 
        help    user id of registrant   
        field   Array [2]   
            handler entity_views_handler_field_entity   
            type    user    
        relationship    Array [5]   
            handler entity_views_handler_relationship   
            base    entity_user 
            base field  uid 
            relationship field  user_id 
            label   user id 
    magazine_id Array [4]   
        title   magazine id 
        help    magazine id of this subscription    
        field   Array [2]   
            handler entity_views_handler_field_entity   
            type    magazine    
        relationship    Array [5]   
            handler entity_views_handler_relationship   
            base    entity_magazine 
            base field  mid 
            relationship field  magazine_id 
            label   magazine id 
views_entity_subscription   Array [1]   
    rendered_entity Array [3]   
        title   Rendered Subscription   
        help    The Subscription of the current relationship rendered using a view mode.    
        field   Array [3]   
            handler entity_views_handler_field_entity   
            type    subscription    
            real field  entity object   


And then as is suggested a whole heap of different places, those fields will be available and if you go to "Relationships" in the Views config then you can also add other entities and their properties. For example 'user' as is the case with "entity_subscription" above, defined by specifying "type" as "user".

Oh, and also - the views_entity_subscription was just a rendered entity, I presume this is for a direct entity/views use, for example when creating a view just of that entity type. 

One final thing: the entity api module itself actually has, in the folder within that module called 'modules' (i.e. sites/all/modules/entity/modules/...) a whole heap of hook_entity_property_info() for the main (core) Drupal entities. This means you can open user.info.inc for example and see how the module authors wrote the entity_property_info for the user entity.