service tax penalty treatment

hi,

a co. has made provision at closing of fin year but could not be paid on time therefore some penalty and interest had to be paid

now what will be treatment of penalty/ interest while there was no provision in previous year whether it should be transferred to P/L a/c or service tax a/c. If in service tax then on what ground because  it is not  a part of service tax.

Thanks & Regards

Abid Husain