The way more than 8 data bytes is sent is a little confusing. They send it 7 bytes at a time with the first byte of every message incrementing by 1, which is called the sequence identifier. So to send more than 8 data bytes, you would essentially be sending multiple messages, each having the sequence identifier one greater than the previous. Three such messages would give you 21 bytes and four would give you 28. I think the simplest way to do this would be with a 'for' loop, putting the data bytes in an array, using the the loop count variable as the sequence ID, and multiplying the loop variable by seven for the offset needed by the array.
Sorry, its been a while since I've been around and active. I've been busy with life things and not had any time for my toys.