Radiation Heat transfer

Hi,

I am trying to do a simple model of radiation but I am having a few problems. It consists just in a lamp heating a piece formed for 3 diferent materials. I am not sure how to modelate the lamp, I have used the option "Boundary heat source" but don´t know which parameters enter on the Cp, density and K. (It is an halogen lamp of 1000 W)
The other problem comes when using the surface to surface radiation option, I have used the option "positive normal direction" for the surfaces facing the lamp and for the face of the lamp that is used as boundary heat source, and surface to ambient radiation for all the others. I don´t know if it is enough to simulate the heat transfer.

Thank you