  The norm kernel of the A=12 system composed of two 6He clusters, and the L=0
basis functions (in the SU(3) and angular momentum-coupled schemes) are
analytically obtained in the Fock--Bargmann space. The norm kernel has a
diagonal form in the former basis, but the asymptotic conditions are naturally
defined in the latter one. The system is a good illustration for the method of
projection of the norm kernel to the basis functions in the presence of SU(3)
degeneracy that was proposed by the authors. The coupled-channel problem is
considered in the Algebraic Version of the resonating-group method, with the
multiple decay thresholds being properly accounted for. The structure of the
ground state of 12Be obtained in the approximation of zero-range nuclear force
is compared with the shell-model predictions. In the continuum part of the
spectrum, the S-matrix is constructed, the asymptotic normalization
coefficients are deduced and their energy dependence is analyzed.
