The intrepid Andrea Tornielli of Il Giornale, an Italian daily, has this piece on his blog. My translation, emphases.
I have learned from a certain source that, contary to what has emerged in certain articles, the response of the [SSPX] to Card. Castrillon’s letter has not been at all negative. The Cardinal was pleased with it, responded to Fellay, and immediately passed the SSPX’s letter to Benedict XVI. Beyond the dead line of the end of June, the Lefebvrites asked for some time – it seems – to seek a way to adhere to the five points.
This is very good. It is consistent with what my own sources have sent me.
However, I am not sure why it should take more time to sign off on things like, "don’t pretend to have a Magisterium above that of the Pope." Bp. Fellay affirmed that he doesn’t think that way and, in a sense, that begins to fulfill that condition.
We wil only know in the future what the SSPX intends to do about the conditions.
If we hear and read harsh rhetoric about the Holy Father, or overarching judgments about the Pope’s ordinary Magisterium, or constant negativity about reunion, that will tell us what they think about the conditions and about dialogue.
But I wager that we are not going to see the SSPX continue according to the status quo ante.
I suspect that if they need time, they are going to use that time to try to muster together the whole leadership of the SSPX into the same orderly rank. I suspect that they are talking intensely, arguing, discussing, persuading on this side and that, how they are going to speak and write in public for the foreseen future.
The SSPX’s negotiations are not just with Rome, but also amongst themselves and with their base of followers.
Pray for them! Pray now!
The old Enemy, the father of lies and divisions will attack them with subtle fury.