SHORT DESCRIPTION: Bandwidth-limiting in Netbackup

QUESTION:
Okay, this is going to be a little confusing, so bear with me:

I'm trying to wrap up a netbackup gig at this client.  The situation is
roughly like this:

They have systems at their own site and a colo site. I have a backup
server
at both of the sites. The client would like to make the offsite backups
occur from the colo site to their office site - that is, across their
network to the colo site, to a local library in their offices.

The network is a little complicated. At the COLO site there are 3 vlans.

One of the vlans goes out through a BIGIP box and is visible on the
internet. This NAT address is the address that is visible from their
office
as well. All of the clients over at the colo site have a back end
interface
on one of the other vlans, and the remote backup slave at the colo site
lives on both of these vlans.

NOW - they only have DNS for the externally visible addresses from both
sites - so the "private" interfaces on all of the hosts are not
available
from DNS.  This has required no end of tweaking of host files on servers

and some other ugliness I won't even go into.

The upshot of all of this is that the first time I started up the
offsite
backups from their colo site to their offices I completely saturated
their
link to the colo site and all kinds of bad juju happened. So I set up
bandwidth limiting by putting in the string of NAT addresses from their
colo site in to the LIMIT_BANDWIDTH statement in bp.conf.  This worked
just
great, and all of the traffic from the colo to their office got
bandwidth
limited, and life was good.

That is - until I realized that this is ALSO bandwidth limiting the
traffic for the NORMAL backups going on over at the COLO site.
Apparently
the bandwidth limiting software just looks up the host name (in this
case
through DNS), sees that the host in question has an interface in the
range
specified, and then does the bandwidth limiting thing.  I only wanted it

when the traffic was coming through the NAT interface. It appears that
all
of the comparison must happen on the master server, not on the media
server
actually doing the backups.

I don't see any way to get the behavior I want - anybody have any
suggestions??????  This is one of several issues going on and it's all
making my head hurt.