Maven

I asked my isp about creating a new folder and they reckon they cant.

It may be correct as it is just web space and doesn't have a control panel to edit any options.

All i do with it is up load my publisher web site via filezilla

I also tried following this example which i found on goggle but filezilla doesn't have a cpanel to do this either.

http://www.12wonderwebservices.com/results.php?id=199
Add-on Domain:
Uses a subdomain inside your first.com web space but behaves as a completely separate web site with its own primary domain url.
Example: Go to cPanel ->Add-On Domains. Set up addon domain second.com with the folder/username "second" (without quotes). cPanel automatically creates a folder called "second" in your web space complete with its own cgi-bin. You upload your pages into the "second" folder in your first.com web space using your normal first.com username and password. However, when people type http://www.second.com in their browser, they will see whatever new web site you uploaded into the "second" folder. They will also still of course see the usual first.com site if they type in http://www.first.com
When setting up an addon domain in cPanel, do NOT specify the www in the domain name, just type in "second.com" without the quotes.