MSI has the new v2.0.4.0 from 11/25/2013 (also available on Station-Drivers ), which I’m about to try. Interestingly, there are two links to the download, and one points to an older version (v1.3.8.0 from 7/18/2012), which is not available on station-drivers. The installer for that one seems to be broken, but it can be installed manually and seems to work fine. and supports the removal function (which it makes visible before even rebooting), but unfortunately the removal function no longer appears after rebooting.
This is a very interesting report, which should be moved into >this< thread, because it applies the ASMedia AHCI drivers and not the ASMedia ACI ROM modules (resp. "Firmware").