We construct a universal Vertex-IRF transformation between Vertex type
universal solution and Face type universal solution of the quantum dynamical
Yang-Baxter equation. This universal Vertex-IRF transformation satisfies the
generalized coBoundary equation and is an extension of our previous work to the
quantum affine Uq(Ar(1)) case. This solution has a simple Gauss
decomposition which is constructed using Sevostyanov's characters of twisted
quantum Borel algebras. We show that the evaluation of this universal solution
in the evaluation representation of Uq(A1(1)) gives the standard
Baxter's transformation between the 8-Vertex model and the IRF height model.Comment: 58 page