It can be done by editing the CompositeData.xml file to support your glyphs.
CompositeData.xml
- FontCreator ships with a big XML file that describes how each composite should be built and positioned relative to the base glyph.
- When you choose Complete Composites → Composite Data the program reads those rules, inserts the members, and positions/scales them.
- The file is fully editable, so you can add your own radicals, offsets or scaling ratios and then regenerate thousands of glyphs in one go.
- On the Tools menu, click Options, and then click the Advanced to Copy and Open the folder where you can edit CompositeData.xml.
- A reference about CompositeData.xml can be found here: Complete Composites
It might not be perfect, but at least it allows you to add all the required parts (components) in one go.