Set up your scene in Lumion and select the "Panorama" function from the menu in the bottom right
Choose the viewpoint you'd like the panorama to be rendered from using the viewer in the top right, and then "set" that viewpoint using the camera icon above the filmstrip at the bottom of your screen
Once you've set up all of the viewpoints that you'd like to render, select the "VR Panorama" button on the right side of the screen
In the "Panorama Settings" screen the will display, ensure that "Stereoscopic" is toggled to "On" and that the "Target Device" is set as GearVR / Oculus. This setting will work with Scope, regardless of which viewer you are actually using. If you want to make sure that the viewpoints you've set are correct, you can use the "Draft" quality for a faster render, otherwise make sure that the quality is set to "Production". Click the "Start Rendering" button on the bottom right to start rendering your files and save them to your computer.
If you prefer to render an equirectangular image rather than a cubemap, you can do so by selecting "Generic VR Device" as the target device. The process for uploading the equirectangular image is the same as the GearVR format cubemap.
Once your panorama has successfully rendered, upload the image to irisvr.com/panos. Full tutorial here.