This is actually my favorite way to do cuttings. I do it just how I would propagate other things like hydrangeas, crepe myrtles, butterfly bushes etc...
1. Take a cutting like you would a normal winter cutting but just a leave a leaf or 2. May even want to cut the leaves in half depending on cutting to leaf ratio.
2. Score/scratch and apply hormone if desired but not required.
3. Stick in rooting media with same moisture level you would if using a winter cutting.
4. Put it inside a clear plastic tote/storage container. I usually keep this inside my house, 70-75 degrees, in front of a window.
5. Mist the leaves and container generously with water to increase humidity.
6. Close the tote lid and keep lid closed.
7. You can open the tote daily or ever few days for just a minute to get some fresh air. Can also respray some water in the tote if you feel the humidity is dropping. But this isn't really needed as long as you don't keep the lid open for long.