CCXML Dialog object properties

I have a question about the following properties of the Dialog object:

- connectionid
- conferenceid
- duplex

There are no doubts about the values of these properties immediately 
after creation of a dialog. But if the dialog is being joined with another
conference, connection or dialog, there are some doubts about how 
these properties need to be updated (if they need to be updated at all).

Example:

- dialog is initially joined with a connection C1 bidirectionally:

  connectionid = C1
  conferenceid = undefined
  duplex = full

- dialog is then joined unidirectionally with a dialog D2 so that
it listens to it

Does it mean that the updated values should become:

  connectionid = undefined
  conferenceid = undefined
  duplex = half

because the source media stream is now coming from the dialog D2,
not the connection C1?

If the dialog is then joined with another connection unidirectionally,
so that it still listens to the dialog D2, the properties wouldn't be 
updated, right?

In other words, the properties should always refer to the joined connection,
conference or dialog that is the source for this dialog (drives the media 
stream to the dialog), regardless of number of <join> operations. Is this true?