As an alternative, I'd suggest simply turning off the Quarantine in VPOP3, and have the users set up 'Inbox Rules' or 'Message Filters' to filter anything containing '[VPOP3Spam]' in the subject and put it into a 'Junk' folder (you can change that subject text in the VPOP3 Spamfilter settings). That way the user will not see the spam, but they can look in their 'Junk' folder on their email client to see any messages which VPOP3 filtered.
If you have VPOP3 Enterprise, you could set up a 'Message Rule' in the user's settings in VPOP3 to move messages if they have a 'Spam Score' over a certain amount (eg 100)