With the upgrade to WSP 2.1 they broke the Instant Alias functionality and it was a known issue. We are still having the same issue with SolidCP. Is this on the roadmap to fix?
Ben Answered question
WSP 2.1 changed alot with the instant aliases, which is why it works on 2.0 but not 2.1
I did just verify that it creates an record just a wrong one on DNS 2012+ provider which should be relatively easy to fix. (i will add it to the bug tracker)
As far as SolidCP codes go: We actually continued the WebsitePanel project after the project got hijacked by the project leader so most of our base is still WebsitePanel (just with alot of bug fixes, new features and enhancements).