The reason there is no “Sign up to CESM” in the lists is because there is already a version of CESM registered to that account (i.e. preventing signing up for the same thing twice).
To overcome this you can do an in-place upgrade from version 2.0 to version 2.1 but you cannot upgrade any previous version to either the ESM 3 beta, RC 1 or RC 2. You also cannot upgrade between versions of ESM 3.
The first release of ESM 3 (scheduled for Monday 25 February) will be a standalone installer. This means that it cannot be upgraded to from any previous version of ESM. There are a number of reasons for this, mostly revolving around database incompatibilities, but we have built and are testing an upgrade package which will allow an in-place upgrade to ESM.
Regards,
Michel.