[Dovecot] General approach question - am I doing this the right way?

Quick outline of my current working setup:

I'm running dovecot 1.0.5 as an IMAP mail server on my ubuntu home server, which i connect to with my phone and several other machines to check my mail etc.

i use getmail to collect mail from my various pop accounts. getmail filters the mail using spamassassin via a Filter_external, before moving it to my Maildir on the home server.

Then when I connect to the home server from my various machines, IMAP manages the status of all the mail, so unread messages are common etc.

All works very nicely. However I'd like to fix a minor annoyance...

...Spamassassin marks mail as SPAM but the mail client has to do the job of moving it to the Junk folder. I'd like the mail to be filtered on the home server on receipt.

Am I just making things really complicated for myself? Is there a simpler setup for what I'm trying to do?

Thanks in advance for any thoughts or suggestions