svnsync and non-interactive authentication. bug?

While documenting svnsync in The Book, a question occurred to me. I see
that svnsync has --username and --password command-line options, as well as
the related --no-auth-cache and --non-interactive options.

But what happens if both the source and target repositories of your
mirroring process require authentication, and as different users? Are you
just out of luck in terms of getting non-interactive functionality? Is this
a shortcoming of svnsync, or am I overlooking something?

(I admit it -- I haven't tested this to see what happens. It's 4am, and I'm
going cross-eyed, so this mail is as much a TODO that will wind up back in
my Inbox as it is a question for someone else to answer.)

-- 
C. Michael Pilato <cmpilato@collab.net>
CollabNet   <>   www.collab.net   <>   Distributed Development On Demand