If you entered the 1099 INT correctly, it should be the first item that comes up when you go into the foreign taxes section and elect to take the credit. There is an instruction to link each class of foreign income to a separate 1116 form. The first class to come up are 1099 INT. I suggest that you delete the 1099 INT and re-enter it. I just did this in an in process return as a test and that is how it works.
