Damian, my guess is "not likely".
Your remote users will need to have the external file location available when they are away from the office. If I connect when I'm away from the office my computer will have to resolve the path to the location to files. I'm not sure I would make a server directory available outside your filewall. But there are options. You could use VPN to make the system think that you are actually connected internally when you aren't. The downside of this is that your users will have to connect to your network via VPN and then launch the database.
Another possibility would be to create thumbnail images that are actually imbedded in the database and not stored externally.
I hope these suggestions help.
Thanks for your guess , I'll try to fix it using VPN, but I'm not sure about this solution.
Are you using FileMaker 12 and enahnced containers? This will work as the files are located on the server and can be accessed remotely.
Yes, I'm using fm12 and enhanced containers. But, could I add new files located on the server from a remote location?
Is VPN really necessary?
No need to use VPN to work on a database from a remote location,
just forward port 5003 in your router to your server.
Then use your outside ip address to acces the server.
Hope that helps,
Ruben van den Boogaard