Treating my repository as a SVN repo, I get:
svn co http://myrepo/foo/trunk foo
...
foo/
bar/
baz/ -> http://myrepo/baz/trunk
Treati
I decided to write a "simple" perl script to handle all this stuff for me. I've put it recently to github, try it out, maybe it would help: http://github.com/sushdm/git_svn_externals/.
It essentially does git-svn clone for all externals found, and it looks for them recursively, clones, symlinks them in proper places and excludes all .git_externals dirs and symlinks so that you can still use 'git svn dcommit'.
Good luck.