I have not read that particular manifesto myself. The link you provided inferred that the "resistance" was in the spirit and manner of St. Paul to St. Peter. And no one would suggest that Paul was in schism, or was disputing Peter's place as the Holy Roman Pontiff. Likewise, I would assume this particular "manifesto" that you reference does the same thing. I skimmed back through the text of the article and couldn't find a reference to it there though. I did, however, find this exerpt (which seems to dispute your suggestion that he is anything other than totally faithful to the Pope:
By comparison, the SSPX professes its acceptance of papal authority and has entered into papally-ordered negotiations for regularization as an apostolic administration directly under the Holy Father. (As Cardinal Hoyos told the press, Bishop Fellay said to him that "when the Pope calls we run.")