firewall rules for 2 WAN IPs

Hello folks,
I have an older ZyWALL USG 20W setup with 2 WAN IPs. Configured in Ethernet as WAN1 and WAN1:1.
I have 2 subnets, and one of each external IPs is used by one of the subnets.
Now, i have 2 Windows Essentials servers in each subnet with Remote Connect.
For some reason i cannot figure out Firwall rule, to forward remote connect requests to those servers.
Externally, i should be able to browse to each IP and have it open a website, to connect to  WinServer.
rule i created:
from: WAN
to: LAN1
user: any
source: WAN_IP1 (object created with external IP 1)
destination: SERVER1
service: HTTP/HTTPS (2 rules per each service)
access: allow

What am i doing wrong?
prior to splitting router to 2 IPs and 2 Subnets, it worked with
WAN to LAN1 - any-any-any HTTP/HTTPS rule.

thank you