  In 1993 Rosso and Jones computed for every simple, complex Lie algebra g_C
and every colored torus knot in S^3 the value of the corresponding
U_q(g_C)-quantum invariant by using the machinery of quantum groups. In the
present paper we derive a S^2 x S^1-analogue of the Rosso-Jones formula (for
colored torus ribbon knots) directly from a rigorous realization of the
corresponding (gauge fixed) Chern-Simons path integral. In order to compare the
explicit expressions obtained for torus knots in S^2 x S^1 with those for torus
knots in S^3 one can perform a suitable surgery operation. By doing so we
verify that the original Rosso-Jones formula is indeed recovered for every g_C.
