The initial implementation does require the recipient to register within FILR to get the Attachment.
The eMail the recipient get's with the HTM Attachment is very confusing, also all the additional eMails the recipient gets from FILR System. This ends in total lost of mails and attachments.
If the User does have the right to send a public Link with FILR System, then the user basically does exact the same, but within the Groupwise Client.
This makes it easy for the sender and recipient.