Byte array union removes 0's???

[i00]

I have two byte arrays and when I try to union them together the 0's are removed from the second byte array, how do I stop this from happening?

send = Header.Union(buffer).ToArray

'below is psudo code
Header=52,0
buffer=104,0,105,0
send = 52,0,104,105

Thanks,
Kris