Just reporting this yourself will almost surely not work. If you can get your creditors in Singapore to report to the U.S. credit agencies directly, that might work.
I've seen this done to improve credit ratings in the case of U.S. loan applicants with U.S. creditors not appearing on the credit report. I'm not sure if this is still possible at all, however, or if it will work internationally. In the cases that I saw it done, the loan originator (an employee of the bank) requested that the information be added to the credit report by sending related information to the credit rating agencies. This person is paid for having loans approved, so their motivation is to have their applicants look at good as possible. My experience with this is dated, however, and so this might not be allowed at all under current regulations.