I would not advise using IK to fix foot poses - instead try doing it in two steps, use the rotation controls (on the Universal Manipulator or the rotation tool in the viewport, or the sliders on the Parameters or Posing panes) to fix the feet, then, with no parts pinned, use the y translation on the hip or the root (“Genesis” or whatever) to raise the figure, or simply hit ctrl-d (cmd-d for a Mac) to drop to floor if you are not using a prop that requires the figure to be above or below the zero plane.