We present work in progress on the computation of the K-meson vector and
tensor decay constants, as well as the B-parameter in Kaon oscillations. Our
simulations are performed in a partially quenched setup, with two dynamical
(sea) Wilson quark flavours, having a maximally twisted mass term. Valence
quarks are either of the standard or the Osterwalder-Seiler maximally twisted
variety. These two regularizations can be suitably combined in order to obtain
a BK parameter which is both multiplicatively renormalizable and O(a) improved.Comment: 7 pages, 4 figures, talk presented at the XXVI International
Symposium on Lattice Field Theory, July 14 - 19, 2008, Williamsburg,
Virginia, US
