Question:
How do I import old Meter energy totals/registers into Plug and Play Scada?

Answer:
Currently there is a manual entry screen where you can enter old totals. That is a per-meter screen, and it is at 'Edit->Meter Totals'. Select the the 'Enter Manual Reading' link to make visible the text entry fields. Enter the date and readings (under Active Import etc); and press the Set button on the right.