title: R lme4 Plot lmer residuals ~ fitted by Factors levels in ggplot
body: <p>I would like to reproduce lmer diagnostic plots in ggplot2. Particularly, I know that for a lmer model <code>DV ~ Factor1 * Factor2 + (1|SubjID)</code> I can simply call <code>plot(model, resid(.)~fitted(.)|Factor1+Factor2)</code> to generate a lattice-based  Residuals Vs. Fitted plot, faceted for each Factor1+Factor 2 combination. </p>
  
  <p>I would like to generate the same plot, but using ggplot2. I tried using <code>qplot(resid(model), fitted(model))</code> and different variations of that with different arguments, but the information about the factors needed for faceting is not coming through with this (and similar) calls. </p>
  
  <p>I'd appreciate any advise to achieve this, thanks!</p>
  
  <p>EDIT
  The core of my question: given any lmer model, how can I create a data-frame including fitted and residual values AND the Factor information for each value? something like:</p>
  
  <p><code>Factor1    Factor2    Fitted    Resid
      0          0        987       654
      0          0        123       456
  (...)</code>
  I could not figure that out from lmer documentation on the <code>resid()</code> and <code>fitted()</code> functions</p>