Although the SRT 8 & 10kVA units have back-feed relays in the Live and Neutral lines and should technically work for 230V phase to phase when the UPS is configured as single phase-single feed there could be a safety issue.
This safety concerns the XLI output PDU which contains single pole breakers and only opens the one phase as compared to double pole breakers on XLT PDU breakers.  This will create a condition where the L2 (N in a single phase application)  at output PDU would have a potential of 120VAC with respect to Earth (Ground) in standby mode.
As this would create a safety hazardous condition, it is highly recommended to use the proper input wiring for this UPS as outlined in the installation or user manual to maintain the safety integrity of the UPS.  For this reason we recommend using a Transformer thus converting the 2 phase supply to a Phase and Neutral supply by bonding one leg to Earth to create an artificial Neutral.