Regularity of infinitesimal CR automorphisms

We study the regularity of infinitesimal CR automorphisms of abstract CR structures which possess a certain microlocal extension and show that there are smooth multipliers, completely determined by the CR structure, such that if $X$ is such an infinitesimal CR automorphism, then $\lambda X$ is smooth for all multipliers $\lambda$. As an application, we study the regularity of infinitesimal automorphisms of certain embedded hypersurfaces of infinite type.