Show input control by role

Hi everybody,

I'm trying to figure out how to show a input control according to the role.

An example:

if I login as admin (ROLE_ADMIN) and try to execute report R, then input controls A and B should me shown to me. But if I login as user (ROLE_USER), then only input control A should be shown to me (I will get B from built-in user attributes).

Does anyone knows how (and if is possible) to do this?

thanks in advance,

Gabriel