Dear devolper, I know the attachments are still in the roadmap and I can understand that this would be a difficult item to implement. Wouldn’t it however be possible to create a customfield with a link to the external file? If you then could link would have an “open file” button, the file would open with the default program from the operating system.
The issue with this approach is that when you make a backup of your accounting file and restore it on another computer, your links won’t work anymore. So I’m going to say no to this feature request. However attachments will be implemented.