Your hex to binary conversions look right to me, except that you've filled them out with leading zeros, which won't be correct if the first 4 bytes are 4d and 5a.
You don't need to do anything to convert them. Blitz3D is already quite happy dealing with hex numbers. You just prefix them with a $ to denote that they're hex. You can do binary too, but I'm not positive of the character you need to denote binary. I think you prefix it with % as in %0100110101011010
You don't need to do anything to convert them. Blitz3D is already quite happy dealing with hex numbers. You just prefix them with a $ to denote that they're hex. You can do binary too, but I'm not positive of the character you need to denote binary. I think you prefix it with % as in %0100110101011010
WriteInt(File,$4d5a)