  Recently we derived a nonlinear U-spin amplitude relation for $D^0\to
P^+P^-$, $P=\pi, K$, predicted to hold up to fourth order U-spin breaking terms
of order $10^{-3}$. Here we study a similar relation for $D^0\to V^+P^-, V
=\rho, K^*(892), P = \pi, K$, expected to hold at an even higher accuracy of
order $10^{-4}$. We confirm this prediction in spite of a large experimental
error of about 20% in the amplitude of $D^0\to K^{*+}\pi^-$. We also comment
briefly on U-spin breaking in $D^0\to P^+V^-$.
