  Gamma-ray emitting narrow-line Seyfert 1 ($\gamma$-NLS1) galaxies possibly
harbour relatively low-mass black holes (10$^6$-10$^8$ M$_{\odot}$) accreting
close to the Eddington limit, and share many characteristics with their sibling
sources, flat-spectrum radio quasars. Although they have been detected in the
MeV--GeV band with Fermi-LAT, they have never been seen in the very high energy
band with current imaging atmospheric Cherenkov telescopes (IACTs). Thus, they
are key targets for the next-generation IACT, the Cherenkov Telescope Array
(CTA). In a previous work we selected, by means of extensive simulations, the
best candidates for a prospective CTA detection (SBS 0846$+$513, PMN
J0948$+$0022, and PKS 1502$+$036) taking into account the effects of both the
intrinsic absorption (approximated with a cut-off at 30 GeV), and the
extra-galactic background light on the propagation of $\gamma$-rays. In this
work we simulate the spectra of these three sources by adopting more realistic
broad-line region (BLR) absorption models. In particular, we consider the
detailed treatment of $\gamma$-$\gamma$ absorption in the radiation fields of
the BLR as a function of the location of the $\gamma$-ray emission region with
parameters inferred from observational constraints. We find that, due to the
energy range extent and its sensitivity, CTA is particularly well suited to
locate the $\gamma$-ray emitting region in $\gamma$-NLS1. In particular CTA
will be able not only to distinguish whether the $\gamma$-ray emitting region
is located inside or outside the BLR, but also where inside the BLR it may be.
