Megalexx i need your hexediting now how

[Megalexxx]

You can't simply add a byte, since you'll mess up with all the address in your file.

There might be a way if you manage to remove another byte near the one you want to add.
You have to study the code around, and (for example) if there's a "0900" code, you might be able to remove it (it's a NOP instruction).

BUT, this might also not work at all, since digits length are hardcoded. For example, an integer is coded on 2 bytes. If you need to code a value > 65535, you won't be able to do so, even if you add a byte, since the program will read only an integer (so the 1st 2 bytes...).

I need more explainations on what you want to do.