salience

I would find it incredible if MPP Solar inverters and their clones were  NOT compatible with the 2 major brands of solar panels available here in Europe, BENQ and QCELLS. I contacted a retailer of the Inverter WKS II 48V 5kVA - a re-brand or clone of MPP with the same installation instructions, a unit approved here in Europe, and they say the inverter and BENQ are definitely compatible and it is not necessary to ground one or the other pole of the PV array. I am assuming that the answer to all this is contained in the paragraph I posted above about non-isolated inverters:
With a non-isolated inverter, the lack of isolation to the grounded ac service conductors requires that the dc PV array be ungrounded for the inverter to work. While this type of system is operating, the dc PV array actually becomes referenced to ground through the ac output conductors. The PV industry often refers to this system configuration as “ungrounded,” but in reality the PV array is only ungrounded when the inverter is not operating. As soon as the inverter begins producing power, the whole system becomes referenced to ground through the ac service conductors."
It seems then that the instruction sheet for  the BENQ panels assumes that they will be connected to an isolated inverter, and therefore one or the other pole must be grounded. I've not found a contact to write BENQ about this - their instruction manual should be changed to reflect the situation of there being both types of inverter on the market.
SO, has anyone here who is using an MPP / Axpert / etc. inverter grounded a power output pole of their PV array?