  Yields and transverse mass distributions of the $\phi$-mesons reconstructed
in the $\phi\to\mu^+\mu^-$ channel in In+In collisions at $E_{\rm lab}$=158$A$
GeV are calculated within an integrated Boltzmann+hydrodynamics hybrid approach
based on the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport
model with an intermediate hydrodynamic stage. The analysis is performed for
various centralities and a comparison with the corresponding NA60 data in the
muon channel is presented. We find that the hybrid model, that embeds an
intermediate locally equilibrated phase subsequently mapped into the transport
dynamics according to thermal phase-space distributions, gives a good
description of the experimental data, both in yield and slope. On the contrary,
the pure transport model calculations tend to fail in catching the general
properties of the $\phi$ meson production: not only the yield, but also the
slope of the $m_T$ spectra, very poorly compare with the experimental
observations.
