New to Soulseek

Hello, I just registered to Soulseek. A friend of mine said it was awesome and I thought I would try it out.
However; I can't use the client. It tells me that my username is invalid. I kinda figured it's since I have an Ö in my username. Is there anyway to change my user name or in best-case-scenario make the client accept my name?

Thanks in advance!