  The initial condition at the matching scale $\mu_W = O(M_W)$ for the Wilson
coefficient of the magnetic photon-penguin operator in the decay $B\to X_s
\gamma$ is calculated in the next-to-leading-order approximation. The technical
details of the necessary two-loop calculation in the full theory are described
and the matching with the corresponding result in the effective theory is
discussed in detail. Our outcome for the initial condition confirms the final
results of Adel and Yao and Greub and Hurth. We show that --- contrary to the
claims in the second of these papers --- the matching procedure can be properly
performed for infrared divergent amplitudes, i.e. independently of
contributions from gluon bremsstrahlung.
