Issue with XMLSigningSerializer vs. UploadTest_1-2.jar HMAC

Question

We are experiencing a very strange issue.
1.) When we use UploadTest_1-2.jar everything works.
2.) When we use the XMLSigningSerializer.php code, the HMAC differs for some reason, and it will not work.
3.) When using the UploadTest_1-2.jar to generate the HMAC and we hard code it in the XMLSigningSerializer code, it works. 
So it appears as though there is some sort of problem with the HMAC generation when using the example php script given to us by adobe's customer support team. (XMLSigningSerializer.php) 
Has anyone else seen anything like this?  Or is there something we are missing that would make the php code generate a non-working HMAC and the uploadtest jar generate a working HMAC? 
Thank you in advance! 
Joe

Answer 1

This has been figured out by our team:
As it turns out, the xml serializer code for java is slightly different from the php code when serializing text larger than 32767 bytes. So the php code works for small test data sets but fails on the real world data. At any rate, we modified our ruby serializer code to be compatible with the java code.