There is no way to use a free x10hosting domain with another provider. You'll have to look for a free domain provider. One that is frequently used here is co.cc It's free to register there and just set the nameservers in your account there.
Thanks, I bought a domain with EasySpace which I transfered to x10's name servers, I now need to transwer the name servers back to EasySpace. I can't seem to find the option to be able to do so in the control panel.