Flashdevelop has no integrated CVS or SVN file management. To do this is a huge task. The core FlashDevelop team can not start such a project and suggest to use Tortoise.

TortoiseSVN is a Subversion (SVN) client, implemented as a windows shell extension. It’s intuitive and easy to use, since it doesn’t require the Subversion command line client to run. The  version 1.6.7.  was released on january 23, 2010, the most recent version is 1.6.9 released on june 21, 2010.

Away3D source checkout with Tortoise

Dowloading svn files with Tortoise