Removin svn:externals?

Hello all. I'm hoping you folks can tell me that I haven't just trashed
everyone's working copy.

Previously, we had an external item called 'common' in our project-doc
project, so when someone did a checkout, it looked something like this:
=====
D:\temp>svn co -r 1133 http://lynx/ec-svn/trunk/project-doc
A project-doc\data-access-manager
A project-doc\data-access-manager\ec012-QS20-data-access-manager.doc
A project-doc\data-access-manager\ecd028-QS09-DAM.doc
...
A project-doc\Specs\Internal\Master IDX 4010 Spec 07-01-2003.xls
A project-doc\Specs\Internal\X124010_to_IDX835_matrix.xls
 U project-doc

Fetching external item into 'project-doc\common'
A project-doc\common\up-cyan.gif
A project-doc\common\EC_Doc_Format.css
Checked out external at revision 1137.

Checked out revision 1133.
=====

However in revision 1136, I did the following:
svn pd svn:externals project-doc
svn add project-doc\common

This was because some users simply access svn via a browser to download
docs, and svn:externals objects don't show up in the web interface.

However, whenever someone tries to update a pre 1136 WC, they get the
following:
=====
D:\temp\project-doc>svnversion .
1133

D:\temp\project-doc>svn up
A 033-CSI
A 033-CSI\ecr033.01-CSI.htm
A 033-CSI\ecc033.02-CSI.htm
svn: Failed to add directory 'common': object of the same name already
exists
=====

OK, one might think, the WC 'common' is no longer a versioned resource,
so just delete it, and allow the new 'common' to be added:

=====
D:\temp\project-doc>del /F /S /Q common
Deleted file - D:\temp\project-doc\common\EC_Doc_Format.css
Deleted file - D:\temp\project-doc\common\up-cyan.gif
Deleted file - D:\temp\project-doc\common\.svn\dir-wcprops
Deleted file - D:\temp\project-doc\common\.svn\empty-file
Deleted file - D:\temp\project-doc\common\.svn\entries
...
Deleted file -
D:\temp\project-doc\common\.svn\wcprops\up-cyan.gif.svn-work

D:\temp\project-doc>rmdir /S /Q common

D:\temp\project-doc>svn up
A common
A common\up-cyan.gif
A common\EC_Doc_Format.css

Fetching external item into 'common'
svn: Working copy 'common' locked
svn: run 'svn cleanup' to remove locks (type 'svn help cleanup' for
details)
=====

I think the problem is that svn processes svn:externals before it
processes property adds/deletes? Is there any way out of this besides
"don't do that", or does everyone have to scrap their current WCs and
checkout from scratch?
 
Thanks,

Dominic

-- 
So, I've made peace with the falling leaves. I see their same fate in
my own body. But I won't be frightened when I am awoken from this dream
and returned to that which gave birth to me. 
    -Bright Eyes, "Method Acting"