Sending ReportBuilder Archive Files as an e-mail attachment

I want to send a ReportBuilder Archive File to somebody as an attachment to
an e-mail message, using a FastNet NMSMTP component. When they receive it
and click on the attachment icon, I want it to either print or show in the
view mode. I have associated the archive extension, .raf, with my small app
containing an RB Archive Reader, installed on their machine, and, so far so
good.  When the recipient clicks on the e-mail icon it fires up my
application. If I have pre-hard coded the file name, in the properties of
the NMSMTP Component, it works fine by putting the print code in the forms
OnActivate event. The bit I can't figure out is how to pass the file name to
my application and where do I put the code so that it will fire up and
display/print any archive file which comes as an attachment when the
recipient clicks on it.  Having got the file name into my Delphi App, I can
also do stuff like save to a directory or delete if not required etc.

I am using D6 and Win2k.

If this is posted in the wrong group, please advise.

Ian Millward