Service tax credit

Yes, you can. There is no bar on such adjustments, but you need to intimate to the department.

No the eligibility fo credit is if it is used in provding taxable services, therefore the brokerage would not be initially available at all. 

if you can satisfy the eligibility that 1st one is input for 2nd then its possible otherwise not 

I believe there is a miscommunication Madhukarji. As far as I understand, he is saying that he has already paid Service tax under another head, wrongly. Now, he wants that excess payment to be adjusted against the Service tax liability arising under another head. Hence, the question of taking credit does not arise.

Thus, such excess payment should be allowed to be adjusted, provided you make an intimation to the Department. There is a circular as well in this respect.