BB's envsphere is perfectly useable in P7.  IIRC, it was initially developed for P7 before the next iteration was released.  However, IBL would be the mode to introduce ambient lighting to the entire scene to match the skydome lighting.  HDRI for both lighting and skydome also useable in P7.  Glaseye has several excellent skydome image packages over at Sharecg.  No need to buy.