Doctrine many-to-many relationships with onDelete

In a previous article I explained why I now try to put an explicit onDelete on every relation. The problem comes with many-to-many relationships. If you put onDelete: CASCADE in the relationship it gets ignored and the entries survive in your refclass table. I found some page on this but none that really answers the question fully:

 http://stackoverflow.com/questions/1488171/in-symfony-doctrines-schema-yml-where-should-i-put-ondelete-cascade-for-a-many

 http://groups.google.com/group/doctrine-user/browse_thread/thread/2f924ee3b8cd2689?pli=1

 http://trac.doctrine-project.org/ticket/1123

The common theme is if you want an onDelete on a many-to-many relationship then you have to put it on the reference table. But not a single example anywhere. So, let's start with the "friends" nest example in the manual.

Here is what does not work (no error, simply leaves the records behind in FriendReference)

User:
# ...
  relations:
    # ...
    Friends:
      class: User
      local: user1
      foreign: user2
      refClass: FriendReference
      equal: true
      onDelete: CASCADE

FriendReference:
  columns:
    user1:
      type: integer
      primary: true
    user2:
      type: integer
      primary: true


This one won't even compile (well, I didn't think it would):

User:
# ...
  relations:
    # ...
    Friends:
      class: User
      local: user1
      foreign: user2
      refClass: FriendReference
      equal: true

FriendReference:
  columns:
    user1:
      type: integer
      primary: true
    user2:
      type: integer
      primary: true

  relations:

     onDelete: CASCADE



So, how do we change it so it will work? I'll update this if and when I work it out; if you know please let me know.