Hi Mark,
There are a portion of users who have cookies completely disabled in their browser - but they have a universally poor web-browsing experience, so your app won't be any different. At it's heart, in theory, NetTalk can be made to work without cookies, but it's very difficult to do without introducing bugs. So for all practical purposes cookies are "required".
Now when you embed one site _inside_ another site, and the one "inside" wants to use cookies, then things get exciting. The browser gets peeved with this (typically because it's a technique used mostly by marketeers to track viewing patterns.)
So rather than try and convince IE (which, if you could do this, would make the IE feature redundant in the first place) which you probably won't manage, it might be better to "merge" your site with the static one.
The first, and easiest approach -especially with an existing site which is all-static, is to simply move all the static pages to the NetTalk server, and let the whole thing get served on port 80. The only reasons not to do it this way are;
a) port 80 is shared with other sites and
b) the main site is hosted at one ISP (maybe on Linux) and you're providing the dynamic stuff at a separate venue.
The sharing issue will go away with NetTalk 5 - it has the functionality to serve multiple domains on the same IP/Port connection. The hosting issue opens the door to moving the host - ie hosting the site on a dedicated Windows server (or shared computer via a Windows Virtual Machine). There are plenty of ISP's now offering dedicated, or shared Windows servers at very reasonable prices.
Assuming neither of these options is possible, there are a couple things that _might_ help.
a) when you "include" your site inside the "main" site, keep the domain name the same. For example if the IIS and NetTalk server are on the same machine then embed the link as
http://www.mysite.com:88 and not
http://64.12.3.23:88b) run your bit on port 80, using the same domain name, but different sub-domain. For example;
http://dynamic.mysite.comAnd then "bind" IIS to one IP address, and the NetTalk web server to another.
Cheers
Bruce