Donpatt, I never bought the BK-7M. One reason, I too was waiting for the patch. But I still use my E-50. On the E-50, it works the other way around... an OTS may or may not (at the user's option) change the style variation. This is the opposite of Yamaha's philosophy, where selecting a new variation can optionally change the upper & lower voices.
Also: couldn't the variation change AND the OTS change both be part of a User Program ("registration")? Surely this module lets you program two of the 7 switches on the FC-7 for "User Program Up" and "User Program Down"? Good question, I would like to know myself!