Financials for India does not support Open interfaces hence for AP invoice, you need to have a custom code to populate AP_INVOICES_INTEFACE_ALL table with tax line as 'miscellaneous' because India Service tax processor pick only Miscellaneous lines for Processing.

For AR you need to populate RA_INTERFACE table and then Run Autoinvoice import to create the Invoice.For tax information you need to directly populate JA_IN_RA_CUSTOMER_TRX AND JA_IN_RA_CUSTOMER_TRX_TAX_LINES.

You can also use Manual Service Tax Entry form to make the entries.

Regards
Srinivas Gadde.