What are you trying to program it to do? It's my understanding that this is a learning remote and that if it doesn't include what you're looking for you can program it with the device's original remote. :scratch:
The MX-450 has no way to directly input HEX, you would have to input the hex into another remote and then teach the MX-450 from that remote. As there is nothing other than an archival program for the the MX-450 you will not be able to upload directly.