svn:externals to a remote repository requiring a password

Hi,

I've an svn:externals property on a folder in one repository that's pointing
to a folder in another repository. The other repository however does not
allow anonymous checkouts. Is there a way to include the username and the
password in the svn:externals line so that when checking out from the first
repository, I won't get asked the username and password for the second one?

Both repositories are on apache, accessed via https if that's relevant.

Thanks.

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gooli @ www.testuff.com