I need to run my WPF application as OLE object. I apologize that if I make it XBAP-application I could, but how?
Generally I need this cause of I need to access my application from CIMPLICITY.
You need to modify your existed .NET application to be COM visible. it's a quite general question and I may suggest to look at .NET - COM Interoperability and Microsoft .NET/COM Migration and Interoperability. I'm sure there is a very popular issue and you can find much more materials about it.