It doesn't work. I've tried it... with many power amps.
The LMII was simply not designed to be used as a preamp. Period.
The ONLY "wet" output you have is the DI, and it is simply not hot enough to drive at least most, if not all, power amps to full output, and then you have to start using an outboard DI for the board. I suppose if you got a beefy enough power amp whatever portion of its power you could realize might be enough, but I would be concerned about the signal to noise ratio since your input signal would be lower than desired (closer to the noise floor). It would also be extra "expensive" because you'd be paying for Watts you couldn't access. I wouldn't do it, anyway.
Some of their other models have adjustable DI levels that can be set more than twice as hot as the LMII, and those might work well enough, but that doesn't help here of course... just an FYI.