Hello!
As I know it is not possible to embed DIAdem in other applications like e.g. the Acrobat PDF Reader in the Internet Explorer.
What you can do is to use DIAdem as a 'client side server' and communicate via OLE with DIAdem. You have to add a reference to the DIAdem OLE Object in your C# project. Then you can use the DIAdem PicExport command to generate Images from your REPORT Layout (I recommend PNG or WMF image format) and load this Image in your application. Side effect is that you have a read only view for a layout. Disadvantage is that you have to implement zoom functionality in your app. If you need printer output you can call DIAdem with the PicPrint command.
Matthias