[away3d] How to get access to Away3DBuilder ?

[verlsnake]

Away3D with its Away3DBuilder could be the reason for me to switch to
Flash for web 3D content; it really depends on how convenient the
Away3DBuilder does it make for us to create Away3D content. But
unfortunately I cannot get access to Away3DBuilder ... A FlexBuilder
project with 'awaybuilder.WorldBuilder.as' as main target source has
only
built a grey .swf file.
So my (first) question is: How can I get my hands on Away3DBuilder ? A
detailed recipe for FlexBuilder would be great :-) !