Train spamassassin remotely using a single email account set up for both POP and IMAP

I use multiple devices ( desktop / laptop / iphone / ipad ). I use POP because my desktop has extensive folders that I do not want to upload/share with a server, or take up space on my mobile devices. I use spambayes on my desktop, which is the most amazing thing ever. Unfortunately, The built in spam filter for Apple products is beyond bad, so my mobile devices are a trashfire of incoming spam. My thought was to implement spamassassin, with baysian options, and then train it off my desktop spam folder. I think this is pretty straight forward. What would be ideal though is if each device could flag spam, and have the spamassassin on the server continue to learn based on that. I am thinking of setting each device with a POP account that downloads everything. Then a second IMAP account on each device that only syncs the Junk Folder. Am I going about this ass backwards? Is there an easier, obvious, solution I'm not aware of? Any input appreciated.