Notice: This article may contain information for multiple versions of Passpack, be sure and read the section appropriate to your version. How do I know what version I'm using?
Sorry, no you can't.
For technical and security reasons Disposable Logins can only be generated when you have entered your Passpack account with your "usual" login. If you are going to be traveling for an extended period of time and don't know if or when you'll be able to reach a trusted computer in order to generate new Disposable Logins, then you might consider upgrading to one of the paid account for the period of travel. See Prices and features here.
Passpack v8 (Preview)