Errors during updates to externals are not propagated to parent svn command

Hi,
When I update a checkout containing externals, I notice that errors
during updates to the externals are not propagated to the exit code of
the top level svn command.

D:\Projects>svn update trunk
Fetching external item into 'trunk\A'
External at revision 2344.
Fetching external item into 'trunk\B'
External at revision 1251.
Fetching external item into 'trunk\C'
svn: warning: REPORT of '/svn/repo/!svn/vcc/default': 200 OK (http://myserver)
Fetching external item into 'trunk\D'
External at revision 6370.
At revision 6370.

D:\Projects>echo %ERRORLEVEL%
0

If I manually "svn update" just the "trunk\C" folder, then I correctly
get a non-zero exit code.

This occurs with Subversion v1.6.5 on Windows Vista x64.

-- 
Paul Richards