  We study the charge transport statistics in coherent two-terminal double
junctions within the framework of the circuit theory of mesoscopic transport.
We obtain the general solution of the circuit-theory matrix equations for the
Green's function of a chaotic cavity between arbitrary contacts. As an example
we discuss the full counting statistics and the first three cumulants for an
open asymmetric cavity between a superconductor and a normal-metal lead at
temperatures and voltages below the superconducting gap. The third cumulant
shows a characteristic sign change as a function of the asymmetry of the two
quantum point contacts, which is related to the properties of the Andreev
reflection eigenvalue distribution.
