New Web Items from 3.5 in Version 3.0B

I recently watched a presentation about new features in Web Application Designer 3.5. My company currently only has version 3.0B installed, and do not plan to upgrade any time soon. My question is this: is it possible to take advantage of the new web items in WebAD 3.5 by only installing the version 3.5 client-side WebAD, or is it necessary to completely upgrade the entire BW installating to be able to use the new web items?

Thanks in advance.