  We present a new geometric approach to the flavour decomposition of an
arbitrary soft supersymmetry-breaking sector in the MSSM. Our approach is based
on the geometry that results from the quark and lepton Yukawa couplings, and
enables us to derive the necessary and sufficient conditions for a
linearly-independent basis of matrices related to the completeness of the
internal [SU(3) x U(1)]^5 flavour space. In a second step, we calculate the
effective Yukawa couplings that are enhanced at large values of tan(beta) for
general soft supersymmetry-breaking mass parameters. We highlight the
contributions due to non-universal terms in the flavour decompositions of the
sfermion mass matrices. We present numerical examples illustrating how such
terms are induced by renormalization-group evolution starting from universal
input boundary conditions, and demonstrate their importance for the
flavour-violating effective Yukawa couplings of quarks.
