Import bills with taxes as line items when picking system generated GST/PST payable accounts

Question

I'm working on integrating our app with QBO, and stuck with a problem that stops bills from being imported into QBO with taxes as line items.

Same as what I previously did with QB desktop version, I added taxes as line items for bills and picked system generated GST/PST accounts on the line. When I imported the bills, I got errors like "You have either selected a tax liability account on a transaction where it's not allowed, or haven't specified a tax rate along with it.". I'm pretty sure the tax items the accounts associated with had rate set up already.

The same error happened when I tried to do the same thing from QBO web interface. Bills import only worked when I picked GST/PST accounts I created ourselves.

Now I'm stuck and wondering if it's possible to import taxes as bill line items with system generated GST/PST accounts, and how? If it's impossible to do it that way, does it mean I would have to use tax code and tax rate to populate taxes?

UPDATE

I solved the problem myself with some help from an intuit relations developer. Please see the answer I posted below.

Answer 1

So I created a support ticket at Intuit Developer, and one of their developer relations engineers responded me with the following message:

The PST/GST/HST Payable accounts are used internally by QBO to track sales tax collected and paid. You will need to use self-created expense accounts to further track these line items when creating a Bill.

I followed his suggestion and created a couple of sub-accounts under those internal tax tracking accounts that were generated by Intuit, and tried syncing bills again through QBO v3 API. It worked like a charm :)