When you edit a POI in EPE, you have the possibility of selecting a predefined symbols for your POI. I know it does not always display correctly on Win 7 (I have to fix this), but this feature really works when adding a symbol in your Favorites. POI Loader ignores it when making custom POI. Since I have all the bitmaps, I could automatically add the symbols when creating the GPI. Here's what I propose: if no symbol are set in the POI itself, I will use the one from the filename.bmp. If a symbol is set, EPE will add the symbol in the .gpi. If you do not want this, just use the global "Replace Fields" function to replace the Symbol field by "" (nothing).
I will probably not do this right away, but I will look at it. Maybe it is not possible to add one symbol per POI. It would an easy way to add symbols without having to find bitmaps for them. Also, it allows you to have different symbols inside a single POI file.