Get IrScrutinizer, Generate tab, select RC5 as the protocol, enter 3 in the D field and the function number in the F field.  For example Auto file is D= 3 F = 61

0000 0073 0000 000C 0020 0020 0040 0020 0020 0020 0020 0020 0020 0040 0020 0020 0020 0020 0020 0020 0020 0020 0020 0020 0040 0040 0020 0CA8