Boundedness of Pseudodifferential Operators of C^*-Algebra-Valued Symbol

Let us consider the set S^A(\R^n) of rapidly decreasing functions G:\R^n \to A, where A is a separable C^*-algebra. We prove a version of the Calder'on-Vaillancourt theorem for pseudodifferential operators acting on S^A(\R^n) whose symbol is A-valued. Given a skew-symmetric matrix, J, we prove that a pseudodifferential operator that commutes with G(x+JD), G\in S^A(\R^n), is of the form F(x-JD), for F a C^\infty-function with bounded derivatives of all orders.