Afaik Launchpad and Ubuntu SSO are the one and same user/password database. In this sense they're like a Google account or Yahoo account that uses the same username and password for multiple services/sites.
Note: If you login to http://login.ubuntu.com you can manage your launchpad OpenID options.
Try removing any existing Ubuntu accounts and adding them again. That simple step worked for me.
You should be getting a message about authorising the snap daemon (which asks for your local root user password). If not, check if snap works:
snap login
If you don't have snap, there might be something wrong with your Ubuntu (it should be included by default). Snap can, however, be installed:
sudo apt install snapd
If you still cannot add your account, but you only wanted to enable canonical-livepatch, try activating it from terminal:
sudo snap install canonical-livepatch
sudo canonical-livepatch enable <key>
replace < key > with your live-patch key, which can be generated from:
https://www.ubuntu.com/livepatch
Then go open 'software & updates', click on the 'updates' tab, and enable livepatch
Best Answer
From what I'm reading in the Software Center Specifications, and from what I'm seeing as I'm exploring the Ubuntu Software Center on Natty (11.04), the answer is "No".