Hi danilovav, I've been trying to get it all to work but with no succes. To keep the old network running as it is, I want to just put the router and the whole network behind it in the dmz port and forward all traffic from one of the public IP's. The two other IP's I want to have forwarded to seperate vlan's.
I've made a drawing of the situation, sorry about the paint-quality - I don't have visio or my diagrams on this box. 
 http://img514.imageshack.us/img514/3125/drawingr.png
http://img514.imageshack.us/img514/3125/drawingr.pngSettings that I have until now are; 
 dmz_ip     172.16.1.254           IPAddress of interface dmz
 dmz_router    172.16.1.2          
 dmznet    172.16.1.0/24         The network on interface dmz
 lan_ip    192.168.1.1         IPAddress of interface lan
 lannet    192.168.1.0/24         The network on interface lan
 wan1_br    *.*.196.255         Broadcast address for interface wan1.
 wan1_dns1    0.0.0.0         Primary DNS server for interface wan1.
 wan1_dns2    0.0.0.0         Secondary DNS server for interface wan1.
 wan1_gw    *.*.196.53         Default gateway for interface wan1.
 wan1_ip    *.*.196.49         IPAddress of interface wan1
 wan1_ip2    *.*.197.32          
 wan1_ip2_gw    *.*.197.33          
 wan1_ip3    *.*.198.52          
 wan1_ip3_gw    *.*.198.53          
 wan1net    *.*.196.0/24         The network on interface wan1
 wan2_ip    192.168.120.254         IPAddress of interface wan2
 wan2net    192.168.120.0/24         The network on interface wan2
Under IP rules;
3      wan_to_dmz     SAT      wan1      all-nets      core      wan1_ip      all_services
4     router_allow    Allow     wan1     all-nets     core     wan1_ip     all_services
5     dmz_to_wan    NAT     dmz     dmznet     wan1     all-nets     all_services
ARP;
 Publish      wan1      wan1_ip2      00-00-00-00-00-00      
 Publish     wan1     wan1_ip3     00-00-00-00-00-00
Routing table;
 Route      core      wan1_ip2                 1     No      
 Route     core     wan1_ip3              1    No     
 Route     wan1     wan1net              100    No    Direct route for network InterfaceAddresses.AddressFolder/wan1net over interface wan1.
 Route     wan1     all-nets     wan1_gw         100    No    Default route over interface wan1.
 Route     wan2     wan2net              100    No    Direct route for network InterfaceAddresses.AddressFolder/wan2net over interface wan2.
 Route     dmz     dmznet              100    No    Direct route for network InterfaceAddresses.AddressFolder/dmznet over interface dmz.
 Route     lan     lannet              100    No    Direct route for network InterfaceAddresses.AddressFolder/lannet over interface lan.
As you can see, I haven't even started with vlans as I am stuck here - I can't even ping from outside to the "router" in my test-situation :/