We have discussed this feature for one of our next updates later this summer. It's on the development list, along with adding VORs, etc and Compass Roses to the Vector and Weather Mode.
One idea is to be able to touch any point, an airport, fix, navaid, etc and activate (input degree setting), then a "color" radial line would extend off of that point. This would allow adding a radial to any point, even a Lat/Long.
Just some initial thought, we'll have more information as we move forward with this feature. Stay tuned, it's going to be a busy year.