Dissecting conversations

I am continuing working on the new dissector for the exec/rexec 
protocol.  I am now able to extract the first few variable length null 
terminated fields.  The next problem is that these initial fields 
(username, password, etc.) span multiple packets.  At first, I was 
thinking that I could just use a variable to keep track of how far into 
the connection I had been and continue dissecting fields there.  
However, I think that using the conversation dissection routines would 
work better in this case (right?), especially since there could be 
multiple users connected.

I have read through the packet-rlogin.c dissector and README.developer, 
but I am still a bit unclear on how to use the conversation handling 
routines.  Can anyone recommend a simple dissector that uses 
conversations that I could refer to?  I am currently using 
tvb_get_ephemeral_stringz() to pull fields out of tvb.  Would the 
conversation routines give me a new data structure like tvb that 
contains data from each of the packets strung together?  If not, could I 
use tvb_get_ephemeral_stringz() to pull fields out of the conversation?


Thanks!
  Steve