Question about git svn handling svn external

I use a python script which calls git svn clone based on a text file built from the svn externals of the form

dir1 url1 dir2 url2

to create a git project. Each subdirectory of course will have its own .git and point back to the original svn repository so that I can change a particular subdirectory.

For example, I have dirn from urln/trunk built and I want to change it to urln/branches/mybranch.

Is there a good way of doing this without deleting everything under it?

If I wipe out the dirn directory, I would wipe out the externals that came in with urln and I would have to pick up all the entries that follow. I do not want to pick up the external pointer from svn as I might not actually be using all of those. I want to only bring in the entries from the configuration file. Of course, it would be more useful if someone has already done it.

The project that I am on would like to use python for this, but if someone has already written something, the language would not matter.

--
       Sabba     -          סבא הלל        -     Hillel
Hillel (Sabba) Markowitz | Said the fox to the fish, "Join me ashore"
 SabbaHillel@gmail.com | The fish are the Jews, Torah is our water
http://sabbahillel.blogspot.com