Hi Kerry,
Have you added them to the same MethodID? From within Method:Classic, hover over your username in the top-right corner of your browser and click Manage OpenID. If your other account does not appear in the list, click on Add Additional Login... and enter your login credentials for that account. This should link your accounts and enable the Switch Account function in Method:New.
Let me know how it goes.
- Justin
Edit: This will be done automatically for all users once we change our login process.