Running NISTNet in bridge mode -- Please Help

Could some Linux networking guru please help ? I have compiled and
successfully installed NISTNet on a RedHat 9 box. from the CLI, I can
type in 'insmod nistnet' followed by 'insmod mungemod' etc., and
everything works fine. I can also do a 'lsmod' and both modules show
up in the list. So far so good.

I have configured the same Linux box (the one running NISTNet) in a
Ethernet bridge mode, with two NICs, using the 'brctl' utility. I use
'brctl show' and 'ifconfig' to ensure that the bridge is running
correctly.

The Ethernet bridge connects two devices with static IP addresses, and
each can ping the other.

Now the question:
I start the NISTNet CLI utility with 'cnistnet -u' and then type in:
'cnistnet -a 10.11.12.x:4569 10.11.12.y:4569 add new --delay 10000
150'
I get the familiar : addnistnet <details> from the system that the
chnages are now effective.

The question is : does NISTNet work in bridge mode ? If yes, how do I
verify it ?
The reason I have my doubts, is that I do the following experiment:

1. Ping 10.11.12.x from 10.11.12.y or viceversa, and note the
delay. Note that 10.11.12.x and 10.11.12.y are connected via the
Ethernet bridge as above.
2. Start NISTNet on the Linux box with 10.11.12.x and 10.11.12.y
at the two exremities of the Ethernet bridge. Add a delay as
described above.
3. Ping 10.11.12.x from 10.11.12.y or vice-versa, and note the delay

The delay values from 1. and 3. above are more or less the same,
no matter how large the delay is - if the delay is working, they must
be different.

Any hints, suggestsions or ideas would be greatly appreciated. Thanks
in advance for your help.