Yes,
The manual way is the same as the 1.0.1 to 1.0.3 update manual:
BUT you will need to copy over the Portal web.config from the zip: http://installer.solidcp.com/Files/1.1.0/SolidCP-Portal-1.1.0.zip
then go to IIS settings, make sure Windows auth is off for SolidCP Portal, and generate a new machine key.
Every other step remained identical.