Connection to internet (and sync) happens by itself (though Ihave schedule set to "Manual")

I just to a new ROM (my Verizon XV6700 WM5). Everything works great but I
notice that sometimes, the device connects to the internet and synchronizes
(with an Exchange server I have set up) by itself. I have the schedule times
set to "Manual" in both peak-time and off-time in the Sync options, and I
have the "Push email" set to off in the Connections Manager. What am I
missing - why is it doing this by itself? I notice it especially in two
situations: right after a soft reset, and also when I'm connected by USB
cable to a PC to exchange files (it complains it can't connect to the
network). I want the ability to ActiveSync over the air with my exchange
server, but only when I ask it to. Can anyone help?

Mike