concatenation = true

I'm still trying to figure out what's going wrong with the concatenation
= true. It doesn't work for text or binary, for the current snapshot. 
 I notice two interesting things: in access.log there is dump of each
message sent out, plus udh header. However I note that in each case, the
reported length is one greater than should be. For instance for the udh
it reports a length of 6, the message a length of 153. Is this part of
the problem? 

 Help!

Thanks.

Paul.