Perhaps, these words from the very same letter from Pope Benedict would help:
“…On the same occasion, my venerable predecessor recalled that “the Bishop, a successor of the Apostles, is someone for whom Christ is everything: ‘For to me to live is Christ …’ (Phil 1:21). He must bear witness to this in all his actions. The Second Vatican Council teaches: ‘Bishops should devote themselves to their apostolic office as witnesses of Christ to all’ (Decree Christus Dominus, 11)” [38].
…
As in the rest of the world, in China too the Church is governed by Bishops who, through episcopal ordination conferred upon them by other validly ordained Bishops, have received, together with the sanctifying office, the offices of teaching and governing the people entrusted to them in their respective particular Churches, with a power that is conferred by God through the grace of the sacrament of Holy Orders. The offices of teaching and governing “however, by their very nature can be exercised only in hierarchical communion with the head and members of the college” of Bishops [40]. In fact, as the Council went on to say, “a person is made a member of the episcopal body in virtue of the sacramental consecration and by hierarchical communion with the head and members of the college” [41].
Currently, all the Bishops of the Catholic Church in China are sons of the Chinese People. Notwithstanding many grave difficulties, the Catholic Church in China, by a particular grace of the Holy Spirit, has never been deprived of the ministry of legitimate Pastors who have preserved the apostolic succession intact. We must thank the Lord for this constant presence, not without suffering, of Bishops who have received episcopal ordination in conformity with Catholic tradition, that is to say, in communion with the Bishop of Rome, Successor of Peter, and at the hands of validly and legitimately ordained Bishops in observance of the rite of the Catholic Church.
…The Pope, when he issues the apostolic mandate for the ordination of a Bishop, exercises his supreme spiritual authority: this authority and this intervention remain within the strictly religious sphere. It is not, therefore, a question of a political authority, unduly asserting itself in the internal affairs of a State and offending against its sovereignty.
The appointment of Bishops for a particular religious community is understood, also in international documents, as a constitutive element of the full exercise of the right to religious freedom [43]. The Holy See would desire to be completely free to appoint Bishops [44]; therefore, considering the recent particular developments of the Church in China, I trust that an accord can be reached with the Government so as to resolve certain questions regarding the choice of candidates for the episcopate, the publication of the appointment of Bishops, and the recognition – concerning civil effects where necessary – of the new Bishops on the part of the civil authorities."