  In a previous work we formulated a model of semitransparent dielectric
surfaces, coupled to the electromagnetic field by means of an effective
potential. Here we consider a setup with two dissimilar mirrors, and compute
exactly the correction undergone by the photon propagator due to the presence
of both plates. It turns out that this new propagator is continuous all over
the space and, in the appropriate limit, coincides with the one used to
describe the Casimir effect between perfect conductors. The amended Green
function is then used to calculate the Casimir energy between the uniaxial
dielectric surfaces described by the model, and a numerical analysis is carried
out to highlight the peculiar behavior of the interaction between the mirrors.
