At best, you will be able to select it as the Email client in (say)
IE|Tools|Internet Options|Programs or maybe Control Panel|Add or Remove
Programs|Set Program Access and Defaults. You will probably only be able to
do that with some web-based clients that also provide a Windows dll - which
I have to assume would primarily only need to exist so you can set the
e-mail as the default in this way. If that doesn't let you merge via your
e-mail client (and it probably won't) I doubt if anything will.

Peter Jamieson.