Hi Richter Belmont and welcome,
Are you trying to open these attachments from a web-enabled browser form or from the rich client?
From the rich client, you can do it with code but the form would have to be full trust. Full trust means either configuring a certificates or installing the form. Are those viable options for you.
If so, we could whip up some code for you. It could take up to an hour. We'd need you to purchase a support pack via our Web store. Sorry we can't just answer all coding requests for free. Gotta stay in business and that means getting paid for our time.
Thanks for your understanding,
P