well one of the work around for your problem that I can think of is create your final module stright out of the source files instead of the intermediate .ko files. ie
obj-m := final.o
final-objs := BBM/bbm.o BBM/bbm_basic.o etc.
Now I can not gurantee that the above is going to work, it might.
To learn more about the makefiles and the obj-y and obj-m you can refer to