question

Hi there, I'm a developer from Taiwan. I'm recently confused with the tax withholding imposed on foreign app developers. We've asked AMAZON a couple of questions regarding this issue but still would like to hear about how other foreign developers deal with it. We're told that 30% of the revenue of the app distributed on Amazon will be deducted due to the US tax law. However, we're also obliged to pay our own local taxes in our country, which further decreases our actual net profit. So, now I got two questions as to the solutions to lowering the tax or even exemption. a. Amazon will send us the 1042-S form. Does it serve as the paid proof? Does Amazon help us send this form to the our country's government agency based in the US and complete the tax paid proof procedure? If this is the case, we can then take this document and apply to reimburse for the tax payment made in our country. Or should we actually fly to the US and send the 1042-S form to the agency on our own and complete the procedure? b. I've seen in the forum that foreign developers may be exempt from the 30% tax withholding if they fill the Form W7 (or W8BEN form?) on IRS website. What exactly do we need to do to complete all this to reduce or even be exempt from the tax withholding? Thanks.