Avoiding sync for spam

[FredThu]

I'm using Desktop (1.0.1593) on my ubuntu 9.04 laptop, plugged to my Open Source 6 server account ; I set Sync to "on demand" so I'll receive only the "real" messages when I connect with my Edge/wireless key : it's usually from a railway station stop, so I have only 2 mn to send & receive my mails.

The problem is, all the spam are also sync'ed to my account. So it can take quite a while...

I need to keep my current setup for spams, kept 2 weeks so I can check back when I come back to a real connection or to the office. How can I tell Desktop not to sync the Spams, but all other mails - including those already sorted to folders on the server ?

TIA, Fred

[FredThu]

Isn't there a way to fix this, please ?