I have also been unable to find a simple way to do this. One way I thought of, although lengthy would be to:
save using ACAPI_Automate
open the mod file using ACAPI_Automate
get details of every element in the mod file using ACAPI_Element_GetNum and ACAPI_Element_Get
reopen the original file using ACAPI_Automate
create all the elements using ACAPI_Element_Create
I only use archiCAD 9. In version 10 there is elemet.drawing that may do this???