problems with initial values of Buffer block

Hello,

I want to process 5 bytes at every sample time in Simulink, but the input is a bitstream. I have to do some conversions like this:

bitstream -> Buffer (Output buffer size = 8) -> Bit to Integer Converter (Number of bits per integer = 8) -> Buffer (Output buffer size = 5) -> process

The problem is, the first 6 bytes are all zeros because of initial values in Buffer, so the bytes 1, 2, 3, 4 and 5 cannot processed together at the very same sample time. How to solve this problem?

Owen