Question : Netscreen 5gt MIP help

I have a netscreen 5gt (not 5gt plus) and I set it up in work/home port mode.

I have 1 webserver and one sql server
I want the webserver to be on one network (home zone 10.10.10.0/24) and the SQL server in the (work 10.10.20.0/24) zone (which would be my internal office LAN).

The webserver needs to pull data from the SQL server.

I was told by a netscreen rep that I could create a DMZ by creating a MIP (mapped IP) from the home zone to the work zone.

When I try this

Mapped IP: 10.10.10.2
Netmask: 255.255.255.0
Host IP Address: 10.10.20.2
Host Virtual Router Name: trust-vr

I get an error

one ip in range (10.10.10.0 - 10.10.10.255) is used by interface ethernet2!
Mip: cant be added

I know it is not a public ip address but how can I get a computer in the 'home' zone to talk to a computer in the 'work' zone?

Is there a better way to create a DMZ and secure Trust zone with a 5gt?

Answer : Netscreen 5gt MIP help

I'm guessing this is related to this other question, take a look at that one first and let me know if you still need any help on this one.
http://www.experts-exchange.com/Networking/Q_21877349.html

Jim