Sorry, I can't really help you more than Razor has indicated. Keys are simply a long number, represented either in decimal or hexadecimal. Subsequent formatting for entry into any given receiver may require you to insert leading zeroes (very unlikely) or split the number up into blocks by inserting spaces or some other character.
As you say, the key has a 'type' or prefix of 1 byte (two digits) hexadecimal, and the rest of the key it is clearly asking for in decimal, so if you have it in hex, you must convert it.
Check any text key files (like a s*ftcam.key file) for actual keys and lengths etc.
Perhaps if you tell us what receiver you have, then somebody can help you more.