Disallowing FTP to certain users (Pure FTP)

I need to disallow certain users ftp access - I run an ASP type service so certain clients need to access to the files in their account.

I've come across the /etc/ftpusers method, but unfortunatly this only works with pro ftp . I'd really rather not have to switch back to pro given it's history of problems, however I really need to block clients from downloading files.

I've done a google search and come up with nothing, any suggestions?

Thanks

 

Basically, I don't mind them accessing cPanel since I've set up features to only allow them access to their email settings and webstats, the rest is all gone.

Just need to lock them out of ftp but the /etc/ftpusers is a proftp thing only.