Any way to recover from this mistake?

I installed Vista RC1 Public, which I downloaded from a direct link to
the ISO that someone posted on Slashdot. I didn't realize I needed to
get a product key. When it prompted me, I selected Vista Business since
that is probably what I'll buy when it's released.

Once the activation nagger started coming up, I realized I needed to go
through the registration process to get a key. So I did so. When I
enter the key I received into the activation dialog, I get an error:
"The product key you entered will not work with this edition of Windows
Vista(tm). You mus either run Windows Vista(tm) Setup or enter a
Windows Vista(tm) Business product key".

So, first of all, is there any way to get a Vista Business key from
Microsoft, or is that not covered by the public beta program?

Second, if that's impossible, do I need to completely wipe and
reinstall, or can I somehow revert to non-Business Vista without doing that?

In case it matters, this is the x64 edition.

Thanks,
Jeremy