Hi Francesco,
I am attaching a simple code which explains how ACM can be configured to achieve ADC sampling rate of 1.5MSPS. (I have set SCLK as 100MHz, therefore I could achieve 1.5MSPS through ACLK=25MHz setting. If you want 2MSPS, then you can configure SCLK=64MHz and program the ACM registers such that you will get ADC_CLK=32MHz. Change the trigger freq appropriately).
Let me know if you need more details.
--Prashant