¤ How I can use different version of the same assembly in one project?
¤ Ex: microsoft.office.interop ver 11.0 (for Office 2003) and ver 10.x (for
¤ previous Office version).

You can't. If you are supporting multiple versions of Office then you will have to use late binding
or the library of the earliest version of Office you intend to support.

How To Use Visual Basic .NET for Binding for Office Automation Servers
http://support.microsoft.com/kb/304661/EN-US/

INFO: Writing Automation Clients for Multiple Office Versions
http://support.microsoft.com/kb/244167/EN-US/

Paul ~~~ pclement@ameritech.net
Microsoft MVP (Visual Basic)