  We analyze the Ansatz of separability for Maxwell equations in generically
spinning, five-dimensional Kerr-AdS black holes. We find that the parameter \mu
introduced in a previous work by O. Lunin can be interpreted as apparent
singularities of the resulting radial and angular equations. Using isomonodromy
deformations, we describe a non-linear symmetry of the system, under which \mu
is tied to the Painlev\'e VI transcendent. By translating the boundary
conditions imposed on the solutions of the equations for quasinormal modes in
terms of monodromy data, we find a procedure to fix \mu and study the behavior
of the quasinormal modes in the limit of fast spinning small black holes.
