How you tackle this depends on how many commands your expecting to react to and the syntax they use.
In the example you supplied you could do a simple string comparison for the entire command (ka 00 01) and react on that but if you have lots of commands with varying parameters then this will not be flexible and maybe consume a lot of Arduino resources.
You could also break the commands down so you start with the base command (ka) and it's two parameters (0x00 0x01) and then parse these. This will require more programming but should consume less Arduino resources in the long run.
To properly emulate a device you should also determine if/what the response to a particular command is and send it back (in this case probably something like 'a 01 OK01x'). This should keep the sender device happy and maybe unlock more options.