I considered using the load/unload hive commands, but the issue is to copy the structure of HKLM to HKCU for some reason - simple export/import won't work.

You might also consider using the REG command to export the HKLM, then read in each line, modifying it as needed, and either using WriteValue to write to the registry, or simply writing the modified lines back to a file and importing that file.

Glenn