Voucher entry

You can opt for journal..ensure your grouping of professional charges under direct incomes if it is your main income...and while passing the entry debit the party with 22900 and credit professional/consultancy charges with 20,000..service tax with 2800...and Sbc with 100...grouping of SBC in duties and taxes liablities side

If you ae usuing Tally you can opt Sales Voucher mode so that Sales Register can be extracted every month to find out the Service Tax Liability.

If Professiona charges is direct income, sale entry is enough rather then Journal voucher.