Static NAT pass-through; can not get to work

I am not having any luck getting a static NAT pass-through to work.

BM3.8/NW6.5 all patched to the latest patches (no betas). IPFLT is NOT
loaded.

My internal network on one LAN all have 10.100.xxx.xxx private addresses.
Dynamic NAT works great.

I have secondary public IP addresses bound to my public NIC. Static NAT
mapping between the secondary public IP addresses and the couple of
individual private addresses work just fine. In other words, all has been
working fine.

I need to give one of those internal resources its public IP address
(change it's private to its public).

OK, I went into the NAT table and changed the proper public <-> private to
public <-> public (identical addresses). I changed the internal computer
to it's public address/mask with the same default gateway the server is
using. The internal computer can now only ping itself; can't even ping
it's default gateway. I did reinitialize, and also restarted. I can not
get the pass-through connection to work.

Any thoughts will be well received.

Bob