For BDC and BAPI, you need authorization of particular Transaction. However you can achieve by following way.
1) you can create a background a job for the user which have authorization of those transaction by using JOB_OPEN,JOB_SUBMIT,JOB_CLOSE Function Modules.
2) give following authorization object for scheduling background job.
a) S_BTCH_JOB
b) S_BTCH_NAM
3) Now Run a Program from Branch head user. It will schedule a program though user which has full access of AS02 Transaction.