You can allow adding new attachments using the eCandidus™ Webtop by adding a configuration entry that points to the location of the External Directory setting.

The configuration setting is set using the IIS Manager:

 

Once setup, the attachment screen changes:

 

Note that now on the right side there is a new area which can be opened by clicking on the arrow:

 

Now we can add files to be added:

 

And uploaded: