tried to set a password from the registration email, got the error
"The email julian [edited] is not associated with any eBay userids in our database. Please contact us for further assistance and we will respond ASAP.
Please contact us for further assistance and we will respond ASAP."

Hello Julian,
Thank you for your question about registering. The issue appears to be the plus sign (+) in your email address. Our mail-passwd utility doesn't allow the plus format.
Do you have another email address (or a different version of the email address you are trying to use)? If so, please provide it so that we can store it into your profile. We are happy to help.