its a known issue. i believe there is a work around using the 'Raytype Switcher' production shader. this sits in your A+D material diffuse slot and allows you to define the colour of bounced, reflected, refracted etc rays. i believe jeff patton has a good blog entry on the unlocking and use of this shader -
http://jeffpatton.cgsociety.org/blog/archive/2008/1/
let me know if that works - haven't this issue for a while so not tried this work around.