If I get it right I think that you do not need to set your router for website access as you are able to get to sharedIP page from outside. However you need to set static internal IP for your server on your server and in ISPConfig.
EDIT: I just find out on the top of this thread that you have already static IP from your router so skip to step 2. I will leave the step 1. here for others to have it.
iface lo inet loopback
iface eth0 inet static
address xxx.xxx.xxx.xxx /here you need to put your static internal address/
netmask 255.255.255.128 /this has to be your routers netmask/
network xxx.xxx.xxx.yyy /this has to be your internal network/
gateway xxx.xxx.xxx.www /this has to be your routers static IP - Internal/
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers aaa.aaa.aaa.aaa /this has to be your Internet providers nameservers/
post-up ethtool -K eth0 tx off
2. In ISPConfig in section Management=> Server => Settings put your servers internal IP into field for IP list.
3. Change all websites IP addresses in ISPManager to your internal static IP address (see img bellow). Afterwards you should be able to access your websites from outside.
You can check my post http://www.howtoforge.com/forums/sho...82&postcount=2
regarding internal and external IP in ISPConfig.
(I did that some time ago when I was on dynamic IP as well. Hope I remembered it right
but better write down all what you do and if something will go southward you'll be able to change all back