You might be able to....
If I remember correctly, they did two systems....the closed (C2) and the open (O2). Both were the same, the only difference was the top cap of the lever; the C2 had a dial whereas the O2 had a cap with no adjuster (the same as on the DH4 and E4).
As far as I can remember, the calipers were the same. In theory, if you used a Mini lever you would convert your closed system into an open one.
I may be wrong....it might be worth trauling the net for a bot.
2015 Stanton Ti Switchback
2006 Specialized Demo 8
2013 Specialized Allez Sport
1999 Santa Cruz Chameleon
1994 Cannnondale Beast of the East (rebuild still in progress)