What TDS for Foriegn currency as Salary

Hi Frndz,

I have a thing to clarify with u. An Employee went abroad on office work for some months. He is getting salary from his Indian company, in addition the Indian company paying INR as per the market rate of US$ with his regular salary. 

The thing is I already stated TDS deduction for his salary. How can I deduct TDS for extra compensation ? can i consider it as regular salary or is there any provisions according?

Pls comment

Thanks in advance.