Hi
You cannot have a salary structure for expats as they will be here for a fixed term. Break the compensation into two parts : one the cash and the other benefits
By Cash I mean the salary which will be paid every month by cheque / bank transfer etc.
The second part could include co. paid accomodation, co. paid car + driver, co. paid club membership etc.
In my co. we have an expat from our parent co. in Uk on deputation from 2 years in India office. We are paying him a fixed amount every month, subject to applicable local taxes and the above benefits.
Before deducting taxes on his monthly compensation, check with the expat on his tax implications in his home country and your finance department on the possibility of dual taxes (where the expat might end paying up taxes in India and his / her home country)
Hope the above info helps.