changing version number in newgem

Question

I'm using newgem to manage my gem and according to the readme you just change the version in the top level file of the gem name. However rake gem is not picking up the gem version i am specifiying.

module mygem
  VERSION = "0.0.1.beta1"
end

when i run the rake task rake gem it builds '0.0.1', not 0.0.1.beta1

is there a rake argument to force it, or where else do i change it to pickup the release. I can change the version number in the gemspec and build with rubygems, but I think this limits the purpose of the newgem gem.