You sure can, mate.
Drag a Cab from the Preset Library area onto the Cab Block in the editor.
Also, you can drag an IR into the Preset library in RM and it's converted to a Kemper Cab automatically (we used to have to use the free CabMaker app for this). I'd assume you should also be able to drag one onto the Cab Block in the editor directly from elsewhere (like the sektop on your 'puter), but that's just a logical assumption.
So, good news for you Steve; you don't need to import to the head via USB stick as was previously the case.