While we're waiting for Nikhil to get his GSoC project finished, the flat file is still your way to do this. The format would be
|51110||jdm29m57||Ben||Reynolds||lBen@YAHOO.COM||51110||EM3F-11W||1||CHRISTINE HAMEL 2||Welcome||1|
follow that with course 2/type2/course3/type3
"Set "Upload Type" to Add new and update existing accounts, and existing user account will be updated."
Warning: errors updating existing accounts can affect your users badly. Be careful when using the options to update.