Super Soft X-ray Sources (SSS) are white dwarf (WD) binaries that radiate almost
 entirely below 1~keV. Their X-ray spectra are often complex when viewed with the
 X-ray grating spectrometers, where numerous emission and absorption features are
 intermingled and hard to separate. The absorption features are mostly from the WD
 atmosphere, for which radiative transfer models have been constructed. The emission
 features are from the corona surrounding the WD atmosphere, in which incident emission
 from the WD surface is reprocessed. Modeling the corona requires different solvers and
 assumptions for the radiative transfer, which is yet to be achieved. We chose CAL87, a
 SSS in the Large Magellanic Cloud, which exhibits emission-dominated spectra from the
 corona as the WD atmosphere emission is assumed to be completely blocked by the
 accretion disk. We constructed a radiative transfer model for the corona using the two
 radiative transfer codes; \texttt{xstar} for a one-dimensional two-stream solver and
 \texttt{MONACO} for a three-dimensional Monte Carlo solver. We identified their
 differences and limitations in comparison to the spectra taken with the Reflection
 Grating Spectrometer onboard the \textit{XMM-Newton} satellite. We finally obtained a
 sufficiently good spectral model of CAL87 based on the radiative transfer of the corona
 plus an additional collisionally ionized plasma. In the coming X-ray
 microcalorimeter era, it will be required to interpret spectra based on radiative
 transfer in a wider range of sources than what is presented here.