Go back and edit the account settings again, you don't have to change anything, and just resave it. It may show up now when you LEFT click on the network manager icon. I noticed a bug like this the other day, maybe its the culprit in your case too.
Otherwise you can use pppoeconf from the command line, you can set it to automatically dial the connection on boot up. The only drawback with this method is that you will have to setup your /etc/network/interfaces file manually. There are plenty of websites that can help you with this (google is your friend). To set up pppoconf is pretty basic though:
Open up terminal and type:
Follow the instructions, they are pretty self explanatory. You have to option to allow the connection to start at boot time.
Just remember that doing this will most probably kill network manager, so make sure you create your interfaces file first.