So i have been trying this myself with no luck.
I got so far as to add my own battery type and Inverter but the program still wants to add another inverter on top of the battery inverter and you cannot add any mppt chargers onto the battery inverter option. I dont want to add a battery system i would like to add a stand alone battery
Another issue is i cant add a grid tie i have to make it a free standing system.
Its as if the program is missing a option of "Grid Connected PV System with Electrical Appliances and Battery.