You can buy them on Ebay - pricy!
http://cgi.ebay.co.uk/Bang-Olufsen-BossDim-wall-light-dimmer-Beo-4-5-remote-/220784604696?pt=LH_DefaultDomain_3&hash=item3367c9b618#ht_784wt_972
http://cgi.ebay.co.uk/Bang-Olufsen-BossDim-light-dimmer-Beo-remote-LC2-dim-/220796183181?pt=LH_DefaultDomain_3&hash=item33687a628d#ht_1170wt_972
What is the experience in using these when 1. Using a plasma TV in the vicinity and 2. How directional are they - do you have to point the remote in their direction to get them to work?