Originally Posted by w_bovine
It's a per account setting. That is, if you have more than one email account you can choose what you want to do...either delete both on phone and server, delete on phone and leave on server, or mark as read on server.
Long press on the account name...it will bring up Account Options in a window. Select Account settings. In Account Settings find Syncing folders. Look for When I delete a message and select it. A window will pop up, and from there you can choose what you wish to do.
I've tried that. I just want to be able to move my emails from my inbox into my gmail trash folder. Doing it your way will completely delete the email.