RoundCube 0.2 Beta has been released. Based on that verion, i've created a new version for ISPConfig 2 today.
Although it's Beta, it contains many bugfixes and improvements.
During testing, i was able to login with username AND
alias@domain.tld.
Also the identity problem seems to be better as well.
user@localhost will change automaticly into
user@domain.tld.
For more information have a look
here.