cisco 11000 and ftp load balancing

I have a customer whos using a Cisco CSS11000 for http and ftp. They
have two servers, one of which is production, the other which is
a staging area for production. Basically when the staging server
is set up and tested, they flip production over to that server
by renaming the text files the 11000 looks for. The problem I'm
having is that when the flip over servers, they also want
to flip over FTP as they have a customer who sends them
a file every night using the load balancer address (right now
it just points them at a specific server). I'm not certain
this can be done. They have some thoughts on doing this at
a server level (servers run wsftpd on FC4) but ideally it
would be great just to use the 11000 to do this.

Thanks for any ideas.