Here is a link to BlueDo. They sell a device to enable you to control your LS20 with a universal remote, but I think it only works on certain remotes.
You can click here
[Link: bluedo.com] and get the C-1024 manual, which gives you instructions, and a telephone number 1-800-322-8346 for the Audio Authority Account Manager, who may be able to give you more information on what kind of learning remote you need.