Export this individual letter (CTRL + E), and for a filename, I chose to use the actual letter name. If multiple letters occur (there are 2 M's in my example) the first SWF is m1.swf and the second is m2.swf. It's important to export these SWF into the same folder that you will be exporting the SWF that will be loading all these individual SWF (or be comfortable with using variable path names to point the main SWF to each SWF loaded into it.