To be perfectly honest with you, I would avoid Zend Server CE on a Windows environment. I'm using it now and I really wish I never switched away from AppServ, it took me an entire day to fix all the problems related to it.
On Linux and Mac, Zend is alright, but Windows causes a lot of headaches.
Personally, I've been trying to move away and deprecate my use of IP.Portal, it practically duplicates IP.Content.
As a software developer, and a senior business manager, I completely agree with the method IPS has chosen to proceed with the development of the newer platform, but can understand the frustration at the lack of ease and documentation to contribute to the customisation of IP.Content pages. Practically, supporting two applications, which offer the same, yet distinct, solutions, is not going to be financially viable, and will lead to further constraints down the line.
All that I can suggest is that we continue to support IPS, and learn basic HTML/CSS. For a website that changes dynamically, such as a forum, I feel that it is imperative that its owners have at least some understand in the technologies employed; you never know when you'll need them.