If you want to use the web site projects you have to have OpenAccess persistent classes inside a library project.
OpenAccess does not use reflection, nevertheless we need some extra code for lazy loading and change tracking. This code is injected by the enhancer. Because the web site project has no real compile step we can not inject our code. This results into the restrictions.
That the OSP is not visible to the wizard is a bug. We will fix that. At the moment the best solution is to just have a OSP in your BO or DAL project and use it from there. It is not necessary to have it in the web site project.
the Telerik team