It appears mail is currently routed through the Groupwise server to the new Outlook system, so it can be found in the sent items folder in your Groupwise account.
Open the registration email and the envelope in the title bar to reveal the link to download the 'Client', then copy the eDocs cert to your computer and you should be able to get it up and running.
Quite a runaround... I had more trouble getting it to work on the Mac than the PC, having had to repeat the install / uninstall process a couple of times before the registration was recognised by DDIS eDocs!
Good luck!