making a plot to show cross-level interaction effects

[maoyimin]

It is convenient to build and estimate a within-between model with panelr package. however, it is not easy to make a plot to show cross-level interaction effects after the estimation with wbm()。To plot the interaction effects, I have to use lme4 package and rebuild the model manually. Can you provide some suggestions to achieve this goal based on the results of wbm()?