UPDATE (1200 GMT): The official news agency of the SSPX, DICI, has now confirmed the following:
Bishop Williamson, as he declared in his interview [to Der Spiegel] does not wish to "hurt in any way the work of the Fraternity"; that is why he accepted, on January 31, the decision of the Superior General [Bishop Fellay] to relieve him of his position as director of the Seminary of La Reja (Argentina). [In French: DICI - permanent link]
__________________________________

The name of Williamson's successor as director of the seminary was not mentioned by Bouchacourt, though rumors indicate that it could be Bishop Alfonso de Galarreta, a Spaniard raised in Argentina, currently living in Madrid.
Related: Der Spiegel interviews Bishop Williamson (in English), including a comment with which all reasonable observers will agree: "Apparently Germany's leftist Catholicism has not yet forgiven Ratzinger for becoming pope."