Hi Luigi,
What version of IDM are you currently using?
With a Oracle 11gR2 RAC User Store: Search is Case-Sensitive. Please see the below.
Integrated Documents
For 12.6.7 if you could configure this it would be detailed here. Unfortunately, I am not seeing a way for this to be done.
Advanced Configuration Options - CA Identity Manager - 12.6.07 - CA Technologies Documentation
I recommend opening an enhancement request for this topic. From the CA Identity Suite Community follow the steps below.
1. On the left side, click "Create an Idea"
2. Detail the requested enhancement to the program. Please include business requirements and any other details.
3. Submit.
The enhancement process is now public. This allows the IDM community to decide what are the most important enhancements to our client base. Thank you.
~Scott Owens