  In this paper I investigate the family of mixed three-point correlation
functions <tau^q gamma^{3-q}>, q=0,1,2, between the integrated Sachs-Wolfe
(iSW) temperature perturbation tau and the galaxy overdensity gamma as a tool
for detecting the gravitational interaction of cosmic microwave background
(CMB) photons with the potentials of nonlinearly evolving cosmological
structures. Both the iSW-effect as well as the galaxy overdensity are derived
in hyper-extended perturbation theory to second order and I emphasise the
different parameter sensitivities of the linear and non-linear iSW-effect. I
examine the configuration dependence of the relevant bispectra, quantify their
sensitivities and discuss their degeneracies with respect to the cosmological
parameters Omega_m, sigma_8, h and the dark energy equation of state parameter
$w$. I give detection sigificances for combining PLANCK CMB data and the DUNE
galaxy sample, by using a quadratic approximation for the likelihood with
LambdaCDM as the fiducial cosmology: The combination of PLANCK with DUNE should
be able to reach a cumulative signal to noise ratio of ~0.6sigma for the
bispectrum <tau gamma^2> up to l=2000, where the most important noise source
are the primary CMB fluctuations.
