What you're looking for (the list of tax rates) is not really what you're asking for (tax agencies).
In any case, this thread answers your question: https://idnforums.intuit.com/messageview.aspx?catid=87&threadid=18930&enterthread=y
Unfortunately, the answer is:
In the current SDK or Services V2, this is a limitation that the tax code Id is not retained due to tax model changes. This limitation will be addressed in QBO Service V3.
Thus, what you're trying to do can't be done right now.