I am pretty sure it you can go from G70 to the BK line but not sure about the reverse. On my BK9 I use Styles from my G1000 ( pre- G70 ) and Styles from collections on CD of other manufacturers as well as lots of older Roland models.
I also just discovered that all my editied Styles and SMF's wil play perfectly on my BK7M. Not really surprized but good to know as I was thinking of selling the BK7M. Pulled it off the shelf yesterday and tried it Midied to my Casio Privia 350. Now I have to decide is it worth keeping for a backup unit.
Best idea is give it a try and good luck.
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Bill in SC --- Roland BK9 (2) Roland BK7M, Roland PK5 Pedals, Roland FP90, Roland CM30 (2), JBL Eon Ones (2) JBL 610 Monitor, Behringer Sub, EV mics, Apple iPad (2) Behringer DJ mixer