I looked at your code page.
You may want to look at the 1132Bs programmers manual page three for examples and page four for the hex coded.
Like A is not 06 the far right two columns indicate A=46 hex or F ASCII
I tried using Docklight Evaluation program [one Smartlabs uses for their SDK examples]
I modified the example code on page 3 to send an A4 for my chime module.
Sent 0x02
got back 0x06 0x0D
Then sent 0x63 0x46 0x54 0x45 0x41.
The chime did sound.
The evaluation mode does not allow me to print out the result codes. So I didn't post the reply from the 1132B after the string was sent.
One thing I did see. The 0x02 had to be sent and then the 0x06 0x0D had to be received back. Before the remaining code was sent. If the 0x02 was in the same string as the remaining code. All I got was 0x15 NAKs back.
If you are just testing by sending an 0x02. You should get back the 0x06 0x0D everytime the 0x02 is sent.
Mine did.
You may also want to try a post in the Smarthome Forums Computer Interface Section.
http://www.smarthome.com/forum/forum.asp?FORUM_ID=17