Assigning Icon and OpenDocument Problem

Hello,

I want to assign a different icon to the saved document of my program that is different from the icon of my program. Just like the MS WINWORD.EXE, the icon of that exe is different with the icon of the MS Word Document (.doc file) created. Is this possible in C++ using MFC? How can I implement this? Another thing, how can I open my saved document, that is using the shell explorer, by double clicking it but it will be opened using a different program? I know that my program that ussually save the document is the one that will be registered under the file type in the registry, is there any way that I can implement this?

Thank you.