If the rear sprocket and brake disc lines up correctly with the countershaft sprocket and rear caliper then it is just a matter of the correct spacers. However, if the spacing isn't correct between the two then there really isn't much you can do other than getting the correct hub.
Ok, if the spacing is correct between the two, it's just a matter of getting the correct spacers for lining up the sprocket and rotor to where they need to be. You can cut the wheel spacers down or even add washers of various thickness to get to the desired length needed for each side.
Again, pics could possibly help with figuring it out.