The Court of Claims has allowed the 10-year statute of limitations provided for the FTC in IRC Section 6511(d)(3)(A).
(3)Special rules relating to foreign tax credit
(A)Special period of limitation with respect to foreign taxes paid or accrued
If the claim for credit or refund relates to an overpayment attributable to any taxes paid or accrued to any foreign country or to any possession of the United States for which credit is allowed against the tax imposed by subtitle A in accordance with the provisions of section 901 or the provisions of any treaty to which the United States is a party, in lieu of the 3-year period of limitation prescribed in subsection (a), the period shall be 10 years from the date prescribed by law for filing the return for the year in which such taxes were actually paid or accrued.
You either itemize the Foreign Taxes paid or take the FTC but can't combine both.