RTC security integration problem

We just discover a potential problem in RTC security integration with our repositories:

Our corporate LDAP includes uids using uppercase and lowercase characters (ex. U0180985 and u0180980). There is no rule for that.
If Im not wrong LDAP authentication process is not key sensitive with the uid but this is not the case for RTC where id IS case sensitive.
The point here is: We are going to use creation process and not import process for RTC user creation so we should know the case of the uid before creation in order to make LDAP uid and RTC id match.
But When we receive user information (from a corporate system) we always receive it uppercase (uid included). This is working for non case sensitive systems but not for RTC.

And the question:
Why RTC user id is key sensitive if ldap uid is not?
Could we change this behavior? How?
Any ideas or workaround for this problem?

Thanks in advance

Regards

Andrs