Sales tax box auto selected and disabled for every product

Hi

We are using the MV edition and allow vendors only from one country. Therefore we want the sales tax box is auto-selected and greyed for every product so that vendors have no choice whether to tick or untick - as sales tax is a compulsory item. How can we do this- Is there a way to do this? Has anyone any idea about this?



Much appreciate your help on this



Thx