A little ProFTP help?

[Rob Brandt]

Quick question to ProFTP users:

I want to confine each user to a subdirectory of their web root.

For example, for user randy, web root is /home/randy/www

I want to confine him to  the /home/randy/www/user_data tree.

The environment is as a web server.  I tried to do this with virtual 
servers but realized that ProFTP handles virtual servers purely on an IP 
address basis only, whereas I have only a few addresses and use virtual 
servers by name in apache.

HowTo?

TIA

Rob