You want to:
Guitar-> [HXFX input]-> COMP/WAH/DST/prefx-> SEND BLOCK-> [HXFXsend(why stereo?you're going mono, here)] -> [KEMPER in] -> KEMPER Preamp -> [Kemper mono send] ->
->[HXFX stereo return] -> HXFX stereo fx post KPpreamp-> [HXFX OUT (L,R)] ->KEMPER STEREO RETURN there you go, it should work, as long as you choose stereo send/return blocks where needed on both HXFX and KP.. (note that this doesn't let you use hxfx post Kemper cab, so you have to choose between having stereo fx between pre and power amp, as in a normal stereo amp loop, or having them post cab, as in a studio setup, but to achieve the latter you can move the stereo send block after the cabs in your Kemper)