Basic IPNAT Question(s)

My simple config is below:

host1:
pcn0: 192.168.1.1/24
pcn1: 10.1.1.1/24
pcn2: 10.1.2.1/24

host2:
pcn0: 10.1.1.10/24

host3:
pcn2: 10.1.2.10/24

Obviously, host1 is the gateway, host2 is connected via pcn1, and host3 
is connected via pcn2. 

pcn0 is considered to be the 'outside world' for this exercise.

I need 192.168.1.10 to bimap to10.1.1.10, so I set the following up in 
/etc/ipnat.conf:

bimap pcn0 10.1.1.10/32 -> 192.168.1.10/32

I have set 'ipnat=yes' and run /etc/rc.d/ipnat start.  Everything seems 
to be running, but my external hosts can't ping that IP.

Do I need to alias 192.168.1.10 to pcn0?  Things seems to work when I do 
that, but I am not sure that I am doing things correctly.

Also, what steps need to be taken to allow systems on pcn2 to reach 
10.1.1.10 via 192.168.1.10?  Do I need to set up NAT on pcn2 as well?

Thank you,

Michael