acronis sql dbo user

Hi,
I have a problem with the installation of acronis backup and recovery 11.5 advanced server trial.

I need to install acronis backup and recovery 11.5 on a separate server from sql database.
I can not get the sql user with sysadmin role then the installation stops with error "create database permission denied in database master."
I tried to manually create the databases used by Acronis but the problem persists.
There is a way to install acronis with sql user no sysadmin ?

thank you

Simone Baldi