Can't helps solve the problem without knowing the error you are getting....however, you are doing the token replacement twice...
expand 'version':project.version, 'mcversion':project.minecraft.version
It shouldn't work this way...but my mod Extrabiomes just went open source last night...the code there might help...specifically look at Wasteland and MountainRidge. The top and filler blocks are not set until later because they can be disabled by the user.
https://github.com/ScottKillen/ExtrabiomesXL
Glad it worked out. In my mods, there is no functionality whatsoever in in the mod_ classes.
As to the SMP Multiverse...will DimensionManager.getWorld(id) work for you?