Composite Sales Order Booking

Hi Experts,

I have got one requirement to book both VAT and service tax in same Sales Order line item. Client wants taxes to be charged on a ratio(say 60:40 or 70:30) of line item value. 

e.g.

Line item value(PR00)=1000 Rs

VAT@5% on 60%=30 Rs  (tax code VAT 3%)

Service tax@14%on 40%=56 Rs (tax code service tax 5.6%)

There will be multiple types of ratios in future. Do I need to make multiple tax codes for VAT and service tax?

Please advice.

Regards

Vikas