While speaking about Chapter 8 of Lumen Gentium, Dr. Miravalle explains that although the Council did not solemnly define Mary's Maternal Mediation, it does not mean that it won't happen some time afterward.  Over 500 Council Fathers petitioned to have it solemnly defined.  We had a similar situation when there were many requests to solemnly define the Assumption of Our Lady at Vatican I, but it wasn't until after the Council that it was done.
Ave Maria!
To Download Audio go to http://airmaria.com?p=7832