Given a symplectic space $W$ over a local field $F$ and a additive character $\psi$ of $F$, we can construct the Weil representation $\omega_\psi$, which can be viewed as a representation of the semi-direct product $Mp(W)\ltimes H(W)$, where $Mp(W)$ is the metaplectic group and $H(W)$ is the Heisenberg group.
My question is: are these all of the irreducible representations of the semi-direct product $Mp(W)\ltimes H(W)$? If it is true, can anybody point out a reference? If it is false, why? Is there any easy counter-example?