Just out of curiosity, Could he by another 4024 and use the stacked inverer set up and get the 240 he is wanting and have each inverter on each leg? and use the 240 on the gen and the internal transfer switches etc.?
"Stacking" a pair of SW4024's will definitely provide 240 (and 120), if that's what's needed, and this is a common configuration among high-end conversions such as Vantare and Marathon. That said, 8KW of inverter power is a lot of output, and is, IMO, overkill for most coaches.
The problems with the internal transfer switch still remain. While stacking the inverters will allow you to switch both hot lines, there is still the issue that the neutrals are unswitched, which means that either the ground-to-neutral bond will have to be removed from the generator, or an external transfer switch will still need to be employed. In either case, the ground-to-neutral bonding relay described in the SW4024 manual will still need to be implemented.