  Within a BUU type transport model we study $\phi$ meson production in
subthreshold Ni+Ni and Ru+Ru reactions. For the first time we included in our
model the elementary reaction channels $\rho+N,\Delta \to \phi+N$, $\pi+N(1520)
\to \phi+N$ and $\pi \rho$ $\to$ $\phi$. In spite of a substantial increase of
the $\phi$ multiplicities by these channels our results stay significantly
below the preliminary experimental data.
