We have measured the nonlinear response to the ac magnetic field in the superconducting weak ferromagnet Ru-1222, at different regimes of sample cooling which provides unambiguous evidence of the interplay of the domain structure and the vorticity in the superconducting state. This is {em direct} proof of coexistence of ferromagnetic and superconductive order parameters in high-$T_c$ ruthenocuprates.
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