Ive got a range of public ip's seems like i can put em all in a range on wan1_ip but i would like to be able to set for example
1 EXT IP to only let SMTP in and out
1 EXT IP using for internal use out surf ftp and so on
1 EXT IP for VPN 
Or should i just set em all in a range on wan1_ip and just make alot of rules ? 
But i think it would look cleaner if i had diffrent Wan_ip can i set up wan2_ip wan3_ip and point them to wan1net ?  
Method I have used is as follows. 
These are in the Address Book
 WAN_IP_1         203.000.000.000      - Substitute with your Extern IP     
 WAN_IP_2         203.000.000.000      - Substitute with your Extern IP
 WAN_IP_3         203.000.000.000      - Substitute with your Extern IP 
Rules Entries. 
1  SMTP           SAT    any  all-nets  wan1  WAN_IP_1  smtp 
2  SMTP_Allow   Allow  any  all-nets  wan1  WAN_IP_1  smtp 
3  WWW           SAT   any  all-nets  wan1  WAN_IP_2  http-all
4  WWW_Allow   Allow  any  all-nets  wan1  WAN_IP_2  http-all
** Edit: Let me know how you go with it.