Linq to Sql Association weirdness

When your dbml designer shows an association, you’d expect to be able to traverse it in code don’t you?

So, funny thing. The Post entity lacks a “PostTags” Field that should be there according to the designer.

After a few minutes of tinkering, I realized that PostTag has no primary key of it’s own. Since in my real application it’s a m:n association table and no entity on it’s own I didn’t use a primary key. But apparently Linq to Sql needs a primary key to work with, so once I changed the table to have a PK magically a PostTags field appeared:

Once again I get how “version 1” Linq to Sql really is, but sadly there won’t be a version 2 since Microsoft is now pushing all resources towards the Entity Framework.

Why not EF? Too complex, once I reach a level of complexity that would justify the use of EF, I use NHibernate.
What I need out of Microsoft right now, is some Linq enabled ORM that’s dead simple with a very DB-centric view that works. Something like Linq to Sql v2.