Putting this here for posterity, even though this is an old ticket.
It's possible using DEBUG, if you can edit the fields. Put the breakpoint in FM RS_COMPLEX_OBJECT_EDIT.
Use SE37 to test your FM, and when it stops at the breakpoint, add your records to parameter OBJECT using UPLOAD FROM FILE.
Would be nice if there were a standard "upload" to fill fields in SE37, and ALSO if it didn't truncate more than a screenful of records.