You might wanna use the SemiStandardBone plugin to weight the toes, although I'm not sure that it is available for English PMDe. You could always try using the JP version of the PMDe just to add the toes and use the English PMDe for further edits on the model.
I remember you recommended that to me, though I didn't try the plug-in you mentioned, because immediately I thought it wasn't going to fit with my model of Miku (I was assuming it was for Tda's Miku model).
I did forget to mention that, by some miracle one night, PMX Editor started working, and I could open my Miku model into it. But, I couldn't find how to save it as a .PMD, and also it's all in Japanese and at the time I didn't feel like exploring everything.
I'll figure something out, though, and I will try to attempt your recommendations.