Why can't I do a trace log when firing a method directive BPM but I can do a trace log on a DMT with the same methods being called as my method directive BPM?

Go back through your trace use this utility (it makes things easier)

Make sure that you are setting / changing any value that needs to be set / changed on the trace. Particularly pay attention to the RowMod its important that the RowMod be set in the right place at the right time since most of the processing is done based on that.