A Challenge for our Ceremonialists

Someone recently pointed me to a question that had been asked in relation to the modern Roman rite:

Is the biretta still allowed to be used in the processional and recessional to the altar?

Is the maniple still allowed to be used?

The answer, which was given by a very good and orthodox Catholic I should note, was that no, they were suppressed in the modern Roman rite. (I mention the context, because this is not a person opposed to liturgical tradition at all. So it is an earnest answer on their part.)

Obviously there is debate about this. We've heard rumours that Francis Cardinal Arinze said the maniple was still fine to use, but then, I have yet to see any formal documentation on this point, and it sounded rather colloquial.

So for the benefit of our priests and seminarians out there who perhaps were wondering if they could employ these things if they so desired, I thought I would throw the question out to our ceremonialists here. What say you to the questions and what proof can you bring forward?