How do I recover my multiplayer account password?

[mulder]

Hi there, I made that account a while ago thinking I would never have to log in again (wrong).
I however can't find any button ingame for recovering or changing my forgotten password. The official website tells me I do not have an account registered on any of my E-mail adresses.
"No biggie, just make a new one" is what one would think. That's not possible either as I'l get the error message -steamID already has a registered account- .
Thanks in advance!!