Yes, you can add an account manually online at www.learnvest.com. When you manually add an account you are adding the balance of an account without connecting it dynamically. This allows you to create a budget as long as you keep your account balance up to date.
When you log in to LearnVest online, click on the Accounts tab in your Inbox. Then click "Connect an Account". In the window that appears, click "Manually Add Account" and enter in the details of the account.
Anytime you would like to update the balance of your manually added account, you can go to the Accounts tab, click on the account, and then click on the balance of the account.