Well, the truly proper tool would be Honda P/N 07908-4690002,
pivor locknut wrench (just confirmed it with the VL Churchill catalogue...)
Found it here:
http://www.partzilla.com/parts/detail/honda/HP-07908-4690002.html $ 90,00,- US though, but will fit several Honda models.
Its a tubed tool mode of hardened steel thus permitting access for the hex wrench to hold the pivot bolt on its set torque, while torquering the lock nut.
The arm welded to its side has a 1/2" drive for your torque wrench and the correction factor (IIRC x10) embossed.
The Ebay tool is shaped like a normal bolt socket with the 1/2" (or 3/4"?) drive in its centre; so when trying to torque it, you'll always risk turning the pivot as well -> unintended increase of torque on the swing arm bearings...
It appears being milled out of stainless steel, so not as rigid ast the OEM part.
So IMHO its quite usefull for occasional removal, not so much for proper reassembly...
hope this helps