Port Forwarding with FVS336G Dual Firewall

None of this is working. So I'm going to use concrete examples.

Let's pretend our external IP address is 22.22.22.22

I want to do the following from the outside

http://22.22.22.22:7777 and that takes me to my web server on http://192.168.0.253 with the standard port 80. That can therefore be http://192.168.0.253 or http://192.168.0.253:80. But it should not be http://192.168.0.253:7777

http://22.22.22.22:7777 should be forwarded to http://192.168.0.253:80
http://22.22.22.22:7778 should be forwarded to http://192.168.0.252:80
http://22.22.22.22:7779 should be forwarded to http://192.168.0.251:80

On LAN IP .253 I've got one web site, on LAN IP .252 I've got a different web site on the same physical server and on LAN IP .251 I've got an IP camera with a built-in web browser polling port 80.

In Security - Services on the FVS336G I create a new service for each one of these:
HOMEWEB TCP Port 7777 7777
DEVWEB TCP Port 7778 7778
OFFCAM TCP Port 7779 7779

In Security Firewall I create a new rule for each of these services:
Service Name as above
ALLOW Always
Send to LAN Server : Single Address
Start (only) the Local IP address as above
Translate to Port Number ticked on and set to 80
WAN Destination : WAN2
...

Locking at the list of Inbound Services this looks exactly as it should:
HOMEWEB 192.168.0.253:80
DEVWEB 192.168.0.252:80
OFFCAM 192.168.0.251:80

As mentioned before I have tried playing around with that Translate To Port field by turning it off, setting it to the same value as the incoming port and setting it to 80. No effect.

It must be something else, somewhere else?

I don't understand why the concept behind port forwarding would be so very different on this Firewall in comparison to all of the other Netgear routers I've worked with like the RP614 or the WGR614...