National Insurance Contributions: How do you claim them on your IRS return?

Hi, all.
I know this is a grey area, but for US expats living in the UK and filing with the IRS:  how do you "get credit" for your NI payments?  Do you treat them as taxes paid?  If so, may I ask how exactly?  There are some who say that this relates to a "Totalization" Agreement between the US and UK? 
Does this hold the answer?
https://www.irs.gov/individuals/international-taxpayers/what-foreign-taxes-qualify-for-the-foreign-tax-credit

Thank you.

NIC is not considered a foreign income tax. It is not creditable on a US income tax return.  Some NIC payments are hypothecated by the UK government towards future benefit payments.

Payroll taxes are distinct from income taxes and you don't get any tax credit for them.