Is a new B3D file spec needed?

With the newly added vertex weight feature, how are the
B3D files created and saved? Any different than before?
Are there specs about writing the weights to the file?

Are the import/export tools for various programs either
broken(not work at all) or usuable but can't save weight
information?
Either way is not good.

I guess the importers/exporters will have to be updated,
but I'm wondering how difficult it may be.

actually, its already working ;)

except for pipeline, which I am having trouble making it work, it coulve been my fault though, i need more investigation on that.

but the Max -> U3d path, works fine with vertex weights

Pipeline needs to be updated since it only supports single vertex weights. The format itself has always supported multiple weights per vert, it's just blitz that hasn't