have you tried using light linking?

under the render menu go to lighting/shading, then light linking, then light-centric... from there, select your mentalrayIbl on the left, and then deselect your text from the right (and the material that's attached to it as well, just to be safe)

only thing is that you'll have to create separate lights for your text... and then you'll have to make sure the light for your text isn't linked to any other objects...