  Let $A$ be a connected commutative $\C$-algebra with derivation $D$, $G$ a
finite linear automorphism group of $A$ which preserves $D$, and $R=A^G$ the
fixed point subalgebra of $A$ under the action of $G$. We show that if $A$ is
generated by a single element as an $R$-algebra and is a Galois extension over
$R$ in the sense of M. Auslander and O. Goldman, then every finite-dimensional
vertex algebra $R$-module has a structure of twisted vertex algebra $A$-module.
