[Tinyos-help] Can I change the content of ACK packet?

[HASHIMOTO Noriyuki]

I would like to add some informations into ACK packet in order to  
implement my MAC protocol in TinyOS 2.0.
But I did not find the code to send the ACK.
Is sending the ACK implemented in the hardware?

Please give me some help.

Thank you,
NORIYUKI.