Getting sign-ups free renewal to apply to an exist

On attempting to sign-up for service with

A Full Domain (FREE!)
(*)I already own this domain and will change my nameservers to DreamHost’s.
[X] I would also like to change my registrar to be DreamHost, and renew
for one year.

I got

This domain … is already in our system!

Anyone know how to get the “renew for one year” in this case? Thanks.

And likewise with a domain that of which DH is the
nameserver-er but not the registrar. I guess this must be a fault at DH, and before I risk trmporarily changing the nameservers to workaround, can anyone suggest a better way?