Can't change password without also changing username because the username is too short

[Nikola Kovacs]

When I try to change my launchpad password, which I have to do from Ubuntu One (login.launchpad.net), it fails because my existing username is too short (2 characters). I don't want to change my username (which, according to launchpad, cannot be changed since I have PPAs), I only want to change my password.

[Peter Lences (peter.lences)]

I have a similar issue. I'm also trying to change my password (https://login.launchpad.net/). I'm getting an error for my existing username (which I'm not trying to change): "Error: Must contain only lowercase letters, hyphens and numbers." Well, it does contain a full stop (period) character. I'm not happy to change it but I tried changing it in the same form but then I got "Error: Because you have a Launchpad account, you need to change your username from Launchpad."
So, similarly to the reporter, I'm not able to change my password.