rsync via tunnel - 3 boxes separated by internet

[Jay Strauss]

Hi,

I have searched the archived, and see this question has come up with
some frequency, but the solution by the original poster is never posted 
or the question is not answered completely.  I have also RTFM (rsync and 
ssh), and I've been trying examples that I have googled.

So here it is again.

BoxA --internet-- BoxB (accessable only by ssh) -- BoxC

I want to backup BoxC to BoxA.  I want the process to originate on BoxA,
That is I want BoxA to be the backup server, the files are stored on
BoxA, and the process of backing up is lauched on BoxA.

I have successfully done it like:
BoxA#: ssh -N -L 873:IP_BoxC:873 BoxB
rsync -arv localhost::ftp/jstrauss ./jay

Where I have rsyncd running on BoxC

Questions:

1) Is there a way to do this without setting up an rsyncd on the target box?


Thanks
Jay