Does anyone know the capabilities and limitations of RDS on a 645?

I recently purchased an iPod adapter from Kensington that displays artist and song information on the iDrive display by using RDS. The problem is that it is only showing about 8 characters which is pretty useless for artist and song info.

Is there any way to increase the visible display on the iDrive console to show more than 8 characters? Alternatively, is there any way to make the characters scroll horizontally so at least I can see the info eventually?