regarding j2ssh subsystem

Hi,
We are using j2ssh to develop a subsystem client for a protocol alike
sftp. Except that we need to send raw xml data across from the client to
the server. 
 
For this, we wrote  
a) fooClient - which is similar to sftpClient
b) fooSubsystemClient inherits from SubsystemChannel 
c) fooMessage inherits from SubsystemMessage
d) fooMessageStore inherits from SubsystemMessageStore
 
In fooMessage we have removed the request id encoding from
constructByteArray and constructMessage methods 
 
When we try to send the data using fooSubsystemClient the data recieved
at the fooServer is seen to be encoded with additional bytes. we could
not find any other code in foo classes which is packing in this data.
 
Is the SubsystemChannel class encoding additional data?
 
If so, could you please let me which classes/methods to look at?
 
 
regards
V.Sarma