Service tax invoice

yes it would be ideal to show service tax amount seprately

Yes it is mandatory to show the amount of service tax saperately.

Rule 4A of Service Tax Rules, 1994 provides every service provider has to issue an invoice within 30 days from provision of service or receipt of advance and requires to include, among other things, service tax payable on the taxable value in the said invoice. Therefore, you have to specify the amount of Service Tax in your invoice. This will also enable your client to avail CENVAT Credit on the same, if applicable.