Self Assessment Taxing

Hope someone can point me in the right direction

I am following DOC 948414.1 to set up an example for self assessment taxing for our client in 12.1.3 --we currently use EBTax for sales in Canada but do not use it in the US since we do not sell to the end user

we don't want to review the feature to see if we will use it in the US for self assessement

I create an regime in US and set up suppliers to as not registered and our US company to use self assessment

but I cannot get invoice nor purchase orders to calculate a tax