Hi, 

although its really simple I needed a while to find the solution how to decode
the B-Format to eight channels. Here it is, if someone else may need it:

  
  a1        =           gaw+gax+gay+gaz         ; LEFT FRONT UPPER 
  a2        =           gaw+gax-gay+gaz         ; RIGHT FRONT UPPER
  a3        =           gaw-gax-gay+gaz         ; RIGHT REAR UPPER
  a4        =           gaw-gax+gay+gaz         ; LEFT REAR UPPER 
  a5        =           gaw+gax+gay-gaz         ; LEFT FRONT LOWER
  a6        =           gaw+gax-gay-gaz         ; RIGHT FRONT LOWER
  a7        =           gaw-gax-gay-gaz         ; RIGHT REAR LOWER
  a8        =           gaw-gax+gay-gaz         ; LEFT REAR LOWER   

            outo        a1, a2, a3, a4, a5, a6, a7, a8

gaw, gax etc. are the four channels of the B-Format, the numering depends on
our studio setup and may be changed of course.