I read in the google forums that all incoming SS messages cause an alert to appear in the notification area. This is bad news for remote control type apps where you might want an app to silently act on messages aimed at it. And how about SI (service) messages that regular handsets act on but don't involve the user? I don't have a G1 but am very interested to know if you can suppress all UI for a given incoming SMS.

Has anyone figured this out?

I'm interested in using SMS messages to trigger a POP/IMAP mail download. Has anyone got that working?

Background:
I want to get all my mail from a linux mail server on my droid. I can connect to the mail server using SSL/IMAP and SSL/SMTP. But right now the phone has to poll. Which is a waste of data, battery and time. I have procmail configured to send an SMS message to my phone every time a new email comes in, but I don't know how to suppress these incoming SMS messages, nor do I know how to use them to trigger the mail client to get the mail.