After reading the manual for the axles it says never to place jack under axles to raise trailer and to refer to trailer manual as to where to place jack. Nothing I have from R-Vision says anything. Does anyone know Jack about jacking?
Whatever the axles are mounted to has to support the weight of the unit so that is a safe place to jack if you have a jack that will fit there. I can't imagine the axles being an unsafe place to jack as long as care is taken not to put any kind of ding or dimple on the axle, especially if it is a torsion axle.
Its not that it is unsafe to jack the axel, its just that the axel will bend if the jack is in the wrong place. I always jack on the frame just behind the rear wheel. This will get the whole side up because your tongue jack will hold the weight of the front half. You may need to raise the tongur jack to its upper limit to do this right.