Passing DefaultCredentials to an FtpWebRequest

[Guest]

I wish to execute an FtpWebRequest under the currently logged in user, but
you can't assign the DefaultCredentials or the DefaultNetworkCredentials
object to the Credentials property on the request.

If I create a new NetworkCredentials object with my username, password and
domain, then it works fine.

Anyone know a way of passing the current user's credentials to an
FtpWebRequest?

TIA,
Bill