Whoops, sorry about the mistakes. That's what I get for posting when I'm only half awake!
The disconnect button is not on the signal strength meter, it's on the data icon (to the left). Here's a picture:
You will see that come up when you tap the icon to the left of the signal meter.
The CABs will definitely be attached to this post. Installing either one will cause the data to disconnect after one or five minutes of inactivity. Note that the data is only inactive when there is no data being transferred, so this won't reduce your data usage. There is an application called
NoData at modaco that will allow you to actually disable your data connection if you desire. I've never used it but I'm pretty sure it works with the Omnia.