Preparing for the Touratech and Nippy Normans parts to arrive, I have bought a torx toolkit from Biltema. It is a 38-part kit which seem to be of reasonable quality, given that it is only NOK 299. It adds to the limited set of tools provided by BMW.
http://www.biltema.no/no/Verktoy/Handverktoy/Kombinasjonsnokler-og-piper/Torxsett-38-deler/
Note that the wrench itself was bought separately for NOK 169 (adjustable head, 3/8″ size).
http://www.biltema.no/no/Verktoy/Handverktoy/Kombinasjonsnokler-og-piper/Skralle1/